Star Trek: Enterprise (ENT) focuses on the 22nd century adventures of Captain Jonathan Archer aboard the Enterprise NX-01 during the early days of interstellar travel. The NX designation indicates that this Enterprise is an experimental prototype; Unlike the starships of the four other Star Trek series, this Enterprise doesn't have deflector shields or phasers, but it does come equipped with a phase cannon and a rudimentary transporter that functions efficiently most of the time.
In the early 22nd century, Captain Jonathan Archer commands a crew at the front lines of intergalactic upheaval as he takes command of the Enterprise, Earth's first warp-speed space vessel. For its maiden voyage, he volunteers to return a wounded Klingon to his home planet over the objections of Earth's Vulcan allies, who do not believe the humans are ready for interstellar travel.
Captain Archer takes command of Earth's first warp-speed space vessel and volunteers to return a wounded Klingon to his home planet over the objections of Earth's Vulcan allies, who do not believe the humans are ready for interstellar travel. The Enterprise discovers interference to destabilize the Klingon Empire by genetically-enhanced Suliban involved in a Temporal Cold War.
As they continue their deep space exploration, the Enterprise crew grows restless after two weeks without contact with sentient life. But, they encounter an abandoned alien ship containing 15 humanoid corpses that were part of a scientific experiment. The horrific sight inspires Hoshi to panic and demand a return to Earth, but Archer insists on continuing the mission and finding out more about the abandoned dead. Trouble comes calling when the aliens conducting the gruesome experiments return and attack Captain Archer and his crew.
The Enterprise investigates an uninhabited Earthlike planet far more dangerous than expected. It proves irresistible to Trip, who persuades Archer to allow his survey team to camp overnight on the planet's surface, unaware of a gathering storm. The strong winds kick up pollen released by flowers that induce hallucinations and paranoia, infecting the crew members visiting the planet. After relocating into nearby caves, Trip, Mayweather, T'Pol, and two other crew members become convinced they are being watched.
After discovering the presence of a damaged Xyrillian vessel, Archer dispatches Trip to assist with its power source problems. He is delighted to have a friendly encounter with one of the ship's female engineers, but it has an unexpected side effect. After discovering that their special moment resulted in his becoming pregnant, he realizes he's had an unwitting experience with alien sex. Archer and his crew must then try and return the rapidly growing alien baby to its mother.
The Enterprise crew alters course to investigate the mystery of Terra Nova, a legendary deep-space Earth colony whose inhabitants mysteriously disappeared decades ago. But when they arrive, they encounter the descendants of the colonists who have become a tribe of human-hating cave-dwellers and more alien than Archer could ever have imagined.
Archer's curiosity about an ancient monastery unwittingly places his crew in the midst of a long-standing interstellar conflict between the Vulcans and their arch rivals, the Andorians.
The sudden appearance of a Vulcan starship disrupts Enterprise's probe of an unusual comet containing eisilium, a rare mineral. Trip discovers that T'Pol is transmitting coded messages to the Vulcan ship. After he learns the content of her communiqués, she reluctantly takes Trip into her confidence about her pending marriage on Vulcan. On their mission to the comet for core samples, Reed and Mayweather use explosives that unfortunately shift the comet's rotation. When the sun rises, the ice crumbles and traps them in a crevasse. Captain Archer reluctantly asks the Vulcans for help to use their tractor beam on the shuttle.
Disguised as locals, Archer and his expedition explore a civilization bedeviled by a virulent ailment possibly linked to a covert -- and anomalous -- nuclear reactor. Determined to find the truth, the captain teams up with a local apothecary, leading to a close encounter between the two.
After receiving a distress signal, Starfleet Command dispatches Enterprise to assist Fortunate, a human freight vessel attacked by Nausicaan pirates wounding the captain. On arriving, they are surprised that Fortunate's acting commander and crew are resistant to Archer's efforts to help them and determined to seek revenge against their attackers, no matter the repercussion
The Enterprise comes in contact with an alien vessel transporting stargazers to observe a spectacular stellar event. They are Borothan pilgrims who have come to see the Great Plume of Agosoria, a phenomenon their religion associates with the beginning of the universe. Archer invites them aboard the ship to witness it, not realizing that the Suliban agent Silik is among them. Archer quickly realizes that Silik is engaged in a nefarious time-traveling mission and must stop him before he can tamper with the course of history.
When an unidentified enemy vessel attacks Enterprise, Archer orders the ship's return to Jupiter Station for weapon upgrades. But, Reed, Tucker, and the crew work frantically to get their new phase cannons operational to meet this new threat. Meanwhile, Archer realizes no one knows Reed well enough to give him a personalized birthday gift. So, he orders Sato to investigate Reed's favorite food.
The fascination with human behavior and culture expressed by Dr. Phlox in his letter to a peer is contrasted by his dissenting view of the crew's treatment of a dying alien race.
When Enterprise comes across a disabled Klingon vessel, Archer dispatches a shuttlepod with T'Pol, Hoshi, and Reed to investigate. There, a hostile female Klingon ambushes them and hijacks the shuttlepod, leaving the Enterprise crewmembers dangerously stranded aboard the Klingon vessel. Now it's up to Archer to take the Klingon under guard and enlist her help rescuing his crew.
Archer and the crew are startled to discover the Vulcan High Command has ordered T'Pol to leave Enterprise and are equally frustrated at her seeming indifference about reassignment. However, T'Pol's last mission as a Starfleet officer proves eventful when a militant faction on Coridan, an alien planet, kidnaps her and Archer. Aid comes in the form of the mercurial Andorians: their leader, Shran, still owes Archer a debt (from the events of "The Andorian Incident"). The Vulcans are covertly backing the ruling faction on Coridan, while the Andorians are aiding the freedom fighters. With the help of the Andorians, Malcolm and Trip rescue Archer and T'Pol over the objections of the Vulcan ship retrieving T'Pol, and Shran considers his debt to Archer repaid.
Trip and Reed are dispatched on a shuttle mission to investigate an asteroid field and are cut off from Enterprise, thereby becoming convinced the starship has been destroyed and that their days are numbered.
En route to the eye-catching Arachnid Nebula, the crew encounters an obsolete Vulcan vessel manned by the Vahklas, a Vulcan sect that embraces emotional impulses. Despite her misgivings, T'Pol allows her curiosity about their lifestyle to get the best of her.
The crew explores a jungle planet that's been turned into a hunting ground by a race of stalkers called the Eska. They hunt indigenous creatures for recreation, one of which contacts Archer as a shadowy woman he imagined as a child.
The Enterprise is invaded by Ferengi marauders, who knock out the crew with sleeping gas and pillage the ship for gold, equipment and slaves.
After hearing of a supposedly haunted alien ship on a desolate planet, Archer decides to cannibalize the wreck to replenish Enterprise's supplies and discovers the vessel is inhabited after all. While exploring the ship, the Enterprise crew encounters some ghostly apparitions and an alien race surviving despite insurmountable odds. Trip helps repair their derelict vessel and is befriended by Liana, an attractive humanoid alien who develops feelings for him.
While exploring a planet, Archer and Mayweather accidentally enter a "military zone" and are detained in an internment prison by an alien race called Tandarans, who are at war with the Suliban. While the Enterprise crew's previous encounters with the Suliban have been disastrous, Archer and Mayweather find themselves held with some Suliban detainees who they believe are wrongly imprisoned. This situation leads to a clash of wills between Archer and the Tandaran commandant.
Hoshi thinks she is to blame for a series of misunderstandings that sent a group of visiting aliens off the Enterprise in a huff. As the Kreetassans depart, a strange, symbiotic alien creature boards Enterprise capturing a few crew members, including Archer and Trip. This unidentifiable parasite cocoons them in its web, feeding off their bodies to survive. With the captured crewmembers' lives in jeopardy, an insecure Hoshi, under T'Pol's command, faces her biggest challenge by finding a way to communicate with the lifeform and persuade it to return to its home planet.
Duty interferes with the crew's first shore leave when the Enterprise is sent to the planet Mazar to fetch a distinguished Vulcan ambassador accused of criminal misconduct. The mission disturbs T'Pol, who's a great admirer of the diplomat.
When Archer and Trip repair a vessel belonging to an alien leader, the Earthmen are repaid with an invitation to their new friend's volatile world.
T'Pol talks Archer into joining the shore-leave party on the planet Risa, where he encounters a troubled alien beauty; Hoshi learns a new language from a local man; a pair of aliens take advantage of Trip and Reed; Dr. Phlox's hibernation is disrupted by Mayweather's injury.
Archer blames himself when the destruction of an alien colony prompts Starfleet to recall the Enterprise to Earth.
The sinister Suliban insist that Archer be turned over to them -- and with Archer nowhere to be found aboard the ship. He's stuck in the 31st century, in a decimated city with Daniels, whose intent is to save the future by protecting the past -- and Archer.
T'Pol entertains Archer and Trip with the tale of a crash-landed Vulcan ship, whose stranded crew lived in disguise among the denizens of a Pennsylvania mining town circa 1957.
Enterprise penetrates the Delphic Expanse hunting the Xindi who attacked Earth, threatening to exterminate humanity. Captain Archer and Trip attempt to learn about the mysterious and antagonistic race. But their zeal to capture a Xindi leads them into a trap.
Waves of spatial anomalies pervading the Delphic Expanse distort the laws of physics. They cripple the Enterprise disrupting power, weapons, and computer systems while searching for the Xindi. These destructive distortions leave the ship's stores vulnerable to Ventaxian pirates who loot critical supplies.
Archer awakes from destroying the Xindi superweapon in the U.S. circa 1944 as a prisoner of Nazis controlling New York City. But he escapes with the help of American insurgents. The crew aboard Enterprise seeks answers for their journey back in time and the changes to Earth's history. They find a dying Daniels on board who tells T'Pol about an alien faction of the Temporal Cold War led by Vosk, now allied with the Nazis altering the events of World War II. Archer, T'Pol, and the Enterprise must defeat the aliens and restore the timeline to return to their time.
Vosk and his people altered Earth's past, threatening to destroy many futures. Frustrated by limited Nazi technology, Vosk offers to return Trip and Mayweather to the Enterprise if Archer assists Vosk in creating his time machine. Vosk releases the prisoners, with Suliban agent Silik taking Trip's form; Silik also needs to stop Vosk. Meanwhile, Alicia's comrades in Nazi-occupied New York learn of Archer's space vessel on the eve of an Allied counterattack. Archer, Silik, and Alicia's comrades attack Vosk's time machine facility to disable its protective shield. Their efforts allow Enterprise to destroy the facility. Daniels returns to tell Archer that the timelines are restored and sends Enterprise home.
Complete episode guide for Star Trek: Enterprise with detailed information about every season and episode including air dates, summaries, ratings, and streaming availability in Japan.
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Archer's awkward breakfast with Reed is interrupted when the Enterprise enters a minefield and Reed has to defuse an explosive affixed to the hull.
Following the ordeal in the minefield, the crew links up with an automated repair vessel that troubles Archer when its computer steals information from the Enterprise's data banks.
Archer is fuming after the Kreetassans refuse to part with parts for Enterprise because of a diplomatic gaffe involving his dog, Porthos, who then falls ill with a mysterious disorder. But Dr. Phlox thinks there's more to Archer's rants than meets the ear.
Archer and Trip visit an alien colony seeking deuterium fuel, but their suspicions are aroused when the planet's drillers prove reluctant to deal with them. Aboard Enterprise, Mayweather's sensors detect an approaching Klingon vessel.
A disturbing incident from T'Pol's past prompts her to seek Archer's help in apprehending a renegade undercover Vulcan agent wanted for smuggling biotoxins used to make weapons.
Returning from covertly observing a preatomic-era alien world on the verge of war, Lieutenant Reed realizes he lost his communicator somewhere on the planet. Archer and Reed return to recover the lost technology, only to find the natives found it first. Captured and interrogated as spies, Archer and Reed find themselves doing even more damage to the culture when they are scanned and found to belong to another race. They face execution and autopsy. Meanwhile, Tucker and Mayweather try to figure out how to activate the cloak on the Suliban cell ship so they can mount a discreet rescue.
As the Enterprise nears a black hole in a trinary star system, radiation from the stellar phenomenon causes the crew to become increasingly erratic and obsessed with mundane tasks. Trip, for example, can't stop tinkering with the Captain's chair, while Phlox is fiercely determined to find the cause of Mayweather's headache. Eventually, crew members fall unconscious one by one, leaving T'Pol the only one left awake to save the ship.
Hoshi is convinced her body's molecules are destabilizing after enduring a traumatic trip through the Enterprise transporter to escape a sudden storm on a primitive planet.
Trip boards a Retellian freighter to repair a stasis pod, which holds an exotic-looking alien female in suspended animation. When the woman accidentally wakes up, Trip discovers she's a kidnapped Krios royal and prisoner, not a passenger. He frees Kaitaama, but her haughty behavior interferes with his rescue efforts when the pair flees the freighter sharing a cramped escape pod. Archer pressures a captured kidnapper to help him locate Trip and Kaitaama.
When a lethal neutronic storm approaches faster than Enterprise can escape, the crew takes shelter in the reinforced but cramped maintenance shafts inside the warp nacelles for eight days. They also provide refuge to three Takret, who aren't exactly honest about themselves. They claim to be stellar cartographers. But, they deserted the Takret Militia due to its corrupt leadership known to seize and plunder alien vessels, killing their crews without provocation. The three have been pursued for weeks by a Takret Militia ship. With the Takret immune to the storm's radiation, the Militia ship's crew attempts to seize Enterprise.
During a solo test mission on Shuttlepod One, Trip is attacked by a territorial alien and forced to land on the night side of a barren moon. As he tries contacting Enterprise, he discovers his Arkonian foe has made an emergency landing nearby. The two contend with each other and then team up as a scorching sun rises and threatens both their lives. The Enterprise soon encounters an Arkonian ship, which initially appears hostile partly due to distrust of T'Pol and Vulcans. But the Arkonian captain agrees to split the search for Trip and his pilot.
Enterprise visits the planet Dekendi III hosting an Interspecies Medical Exchange conference. Dr. Phlox requests the Vulcan delegation provide him with the latest research on a terminal neurological disease called Pa'nar Syndrome without revealing that T'Pol is infected. Pa'nar Syndrome is a rare illness associated with mind melders, a sect ostracized by Vulcan society. A forced mind meld against her will infected T'Pol in the episode Fusion. She tries to keep her disease a secret while Dr. Phlox researches treatment methods. Meanwhile, one of Phlox's wives, Feezal, visits Enterprise to install a neutron microscope and begins flirting heavily with Trip. He is uneasy that a colleague's wife is making overt sexual advances toward him.
Both the Vulcans and the Andorians claim the planetoid Weytahn (or Paan Mokar, as Vulcans call it) in an age-old feud and military conflict erupts again. As the fighting goes on, the Vulcans are willing to discuss cease-fire terms represented by Ambassador Soval. However, Imperial Guard officer Shran believes only Captain Archer can be trusted to mediate the bloody dispute, which drags the Enterprise crew into the tense situation.
The Enterprise finds a small, disabled ship drifting in space and discovers it contains a human corpse. More questions arise when the Suliban and Tholians each claim the craft. Both alien species attack the Enterprise and later each other to seize the derelict.
Following a seemingly successful first contact mission, Archer and Trip are charged with smuggling and imprisoned aboard a penal vessel. When prisoners hijack the ship, Archer and Trip must pass as outlaws.
When a massive alien vessel engulfs Enterprise, non-corporeal beings invade/possess the bodies of Trip and other crew members and hijack their souls. These non-corporeal beings claim to be explorers. But these "wisps" may not plan on giving the bodies back.
Archer is put on trial by the Klingons and accused by a disgraced Klingon officer of having his battle-cruiser crippled by the Enterprise in a firefight, and of aiding rebels of the Empire, but he finds a friend in his defender, Kolos.
When Enterprise diverts to investigate an unusual planetary phenomenon near Earth, Mayweather visits his family after the sudden death of his father, a cargo-ship captain. But his return to his old home, the ECS Horizon, is complicated by family tension. He clashes with his brother, the ship's new captain, and pirates attack the ship. Meanwhile, Archer and Trip invite a reluctant T'Pol for movie night to see Frankenstein and find her reaction surprising. She says she will suggest Ambassador Soval show the movie to every Vulcan newly arrived on Earth.
The rescue of a damaged transport prompts the Denobulan Phlox to confront his prejudices when he treats an Antaran, whose people are sworn enemies of Phlox's. Three other Denobulans are holed up in an underground cave, where Trip, Reed, and Mayweather are dispatched to retrieve them when militants take over a planet.
The Enterprise crew makes first contact with the Vissians, a species with three genders. Trip meets one of the species' third gender, a Cogenitor, a being used for only breeding purposes. After learning how badly Vissians treat all Cogenitors, Trip attempts to help this Cogenitor, even though it directly interferes with Vissian culture.
A scientific research team uncovered the remnants of an alien ship and two frozen cybernetic bodies in the arctic. These aliens soon thaw out and flee Earth, taking the research team with them. Starfleet orders Enterprise to find them, but nothing prepares the crew for just how dangerous these aliens really are - Borg drones
Stunned by the death of former Starfleet rival and friend, A.G. Robinson, in a mountain climbing accident, Archer grudgingly recalls their competitive relationship with T'Pol as they probe a possible dark matter nebula during a shuttle voyage. He describes how he and A.G. broke the Warp 2.5 barrier on the first high-warp test flight that saved the NX program almost ten years earlier. After they confirm the first dark matter nebula, T'Pol suggests Archer name it the Robinson Nebula.
A crafty Tellarite tricks Archer into boarding his ship and kidnaps him to collect a Klingon bounty. They want to punish Archer because he is the only prisoner to escape the prison planet Rura Penthe. As Enterprise pursues, contamination by a stray virus while exploring an uninhabited desert planet prematurely starts T'Pol's mating cycle, the pon farr, where she must mate or die. She finds herself confined to the decon chamber with Phlox.
The Xindi, an alien race from the Delphic Expanse, launched a devastating attack on Earth, causing millions of casualties and massive damage in Florida. As Enterprise returns home, an unlikely source from the future informs Archer about the Xindi and that their next attack will destroy Earth. Capt. Archer and the crew embark on a mission to the galaxy's far reaches to stop the Xindi. Complicating matters are the machinations of a vengeful Klingon still looking to capture Archer.
Enterprise's ongoing pursuit of the Xindi leads to an investigation of an abandoned Xindi vessel on a jungle world. A highly contagious mutagenic virus infects Archer, Hoshi, and Reed and rapidly mutates them into the planet's primal and extinct native beings, the Loque'eque, but T'Pol is unaffected. As Phlox searches for a cure, Trip and T'Pol negotiate with aliens determined to kill all those infected.
Archer, Trip, and Reed return from an alien barter town with Rajiin, an alluring woman seeking to escape her life as a sex slave. But once on board, her beguiling sensuality proves irresistible to the Enterprise crew. She uses her alien mental powers on them to steal biometric data about humans so her Xindi overlords can make a bio-weapon. Two Xindi ships attack the NX-01 to retrieve Rajiin. Meanwhile, Trip and T'Pol attempt to synthesize trellium-D to insulate Enterprise from further destruction by the spatial anomalies of the Delphic Expanse.
When Enterprise responds to a distress call from the Vulcan cruiser Seleya, stranded in the Delphic Expanse, Archer and his boarding team (T'Pol, Reed, and Hawkins) arrive on board to find its crew in a deranged, raging, zombie-like state that quickly manifests in T'Pol as well.
A powerful and lonely telepath named Tarquin begs Hoshi to visit his faraway planet. Smitten with her, he offers to part with crucial intelligence on the Xindi only after she visits. But when Enterprise returns to pick up Hoshi, Tarquin refuses to let her go. He wants her to be his new Companion.
Archer, Reed, and MACO Major Hayes infiltrate a Xindi-Sloth industrial colony that synthesizes the vital explosive material for the Xindi super-weapon that will attack Earth. The trio kidnaps the plant foreman, who allies with them once he learns of the Xindi council's attack on Earth. Elsewhere, Trip, T'Pol, and Dr. Phlox test captured Xindi firearms to create better defenses against them.
After an accident on the Enterprise in 2153, a spatial distortion leaves Archer with a puzzling form of amnesia due to interspatial parasites and unable to form new long-term memories. He wakes up every day not remembering anything from the day before. At one point, he is further confused about finding himself in the future aboard an Enterprise commanded by T'Pol. Twelve years into the future, he wakes up one morning and is stunned to learn the outcome of the human-Xindi conflict. After destroying Earth, the Xindi continued searching the galaxy, determined to annihilate all Humans. The remnants of humanity have settled on the distant planet Ceti Alpha V. Now, Archer learns that he may be the key to undoing this entire tragedy if Phlox's new treatment destroys the parasites without harming him.
The crew investigates a world within the Delphic Expanse with a civilization closely resembling America's 19th-century Wild West. A previously unknown colony of humans is oppressing an alien race called the Skagarans. Archer becomes embroiled in a cultural conflict and sets out to learn how both races got there.
Trip suffers a catastrophic injury in an accident that disables Enterprise inside a hazardous space cloud. His only hope for survival is a transplant from a clone or "mimetic symbiont" which Phlox grows from one of his exotic creatures. Phlox and the crew named the clone Sim. But his rapid growth and replication of Trip's behavior alarm the crew. Archer faces an ethical dilemma as the clone gains sentience and does not want to die from harvesting his organs for Trip's survival.
Acting on a tip from Daniels, Archer and T'Pol time-travel to the year 2004, where the Xindi are building a secret weapon in an abandoned Detroit factory. They must stop the Xindi from destroying Earth with a biological weapon.
After Archer rescues them from their crippled vessel, the Triannons take the Enterprise crew hostage. These alien religious zealots plot to use the ship to eradicate heretics on their homeworld.
Andorian Imperial Guard Commander Shran arrives in the Delphic Expanse and proposes an alliance with Archer, offering to help steal the Xindi's superweapon. Elsewhere, Lt. Talas, an Andorian officer with her own agenda, helps Lt. Reed repair the Enterprise's damaged weapons systems.
Archer seeks to destroy the superweapon the Xindi are constructing by creating an elaborate ruse to fool its designer, Degra, into revealing its hiding place. Archer and Degra are in a shuttle. With Degra suffering from memory loss, Archer tells him they escaped together from a prison and that the Insectoids took power after destroying Earth.
Lt. Reed and MACO leader Maj. Hayes feud over training drills which disrupts Archer and Phlox's investigation of a rescued alien near a spatial anomaly. The dying alien refuses to disclose his motives for exploring the anomaly. As Archer tries to unravel the mystery surrounding the alien, long-simmering feelings explode between Reed and Hayes. Trip's interest in a pretty MACO corporal sparks a heated exchange with T'Pol, who eventually confesses her feelings for Trip.
Archer places Dr. Phlox in control of the Enterprise when the crew requires sedation to survive a trans-dimensional disturbance. This mind-altering section of the Expanse is lethal to humanoids. But Phlox's Denobulan physiology doesn't entirely shield him from its effects, causing hallucinations.
The discovery of unhatched Xindi-Insectoid eggs inside a crashed vessel brings out the paternal side of Archer, who alarms the crew with his obsessive determination to save the embryos.
After pinpointing the site of the Xindi doomsday weapon, Archer plans to sacrifice himself to destroy it. Daniels arrives and takes him 400 years into the future to show him the far-reaching consequences of the Enterprise crew's actions and to beg Archer to reconsider.
While dissension among Xindi ranks festers, Degra gets Archer returned to Enterprise. Archer considers compromising his morals to restore Enterprise's warp capacity after a fleet of Xindi-controlled warships cripple the vessel's engines. Sacrificing his ethics, he attacks an innocent alien ship to get their warp coil to repair the Enterprise's engines and intercept the Xindi superweapon. Meanwhile, T'Pol grows increasingly volatile, prompting her to confide a troubling secret to Phlox. Trellium-D exposure led to her addiction, with withdrawal symptoms weakening her emotional control.
Archer persuades Xindi weapon-designer, Degra, to examine evidence of the plot to pit the Xindi against Earth to prove humanity is not his enemy. When Archer demonstrates they've been manipulated, Degra offers to attempt to delay the launch of their superweapon. Meanwhile, the crew mourns their lost mates, with Trip still coming to terms with his sister's death and wrestling with the recent death of a subordinate. T'Pol confronts her substance addiction to trellium-D.
Before attempting to use a Xindi subspace corridor to reach the Xindi council, the Enterprise crew faces a bizarre encounter with their own descendants on an Enterprise. Captained by T'Pol's son Lorian, the ship warns Archer of an alien attack by Kovaalan ships. Enterprise escapes into the subspace corridor, but attack damage destabilizes the corridor, causing a time shift with the ship emerging in 2037. Will foreknowledge change anything?
Enterprise arrives at the location of the Xindi Council, and with Degra's help and Hoshi translating, Archer makes his plea before the five Xindi races. Archer must prove that the Sphere Builders have been lying and Humanity is not their enemy. While the Primates and Arboreals are already aware of the truth, convincing the other three races will not be easy. The Reptilians and Insectoids refuse to even listen to Archer. Meanwhile, seeing a diminished number of successful timelines with Earth destroyed, the Sphere-Builders arrange a secret meeting with the Reptilians. They seize the Xindi weapon and launch it, protected by five Insectoid ships. Elsewhere, T'Pol and Reed lead a mission inside a Sphere to retrieve its memory core for information about the Sphere network inhabiting the Expanse.
The Reptilians kidnapped Hoshi to brainwash her into cracking the weapon's arming codes. Meanwhile, Archer and his new Xindi allies (Arboreals, Primates, and Aquatics) attempt to stop the arming of the superweapon aimed toward Earth, launching a full-scale assault on the device. When the Sphere-Builders see the weapon is about to be destroyed, they cause at least one sphere to emit massive spatial anomalies destroying many ships. Reptilians and Insectoids escape with the weapon through a subspace vortex heading for Earth.
Archer tries to coax a traumatized Hoshi into using her decryption skills to disable the Xindi doomsday weapon before the Reptilians can use it to destroy Earth. Archer risks his life in a dangerous gambit to intercept the superweapon, sneak by the Xindi Reptilians aboard, and disarm it from inside. Meanwhile, the Enterprise embarks on its own desperate mission to cripple the rest of the spheres.
The Enterprise finally returns to Earth with great fanfare, and the weary crew members face repercussions of their journeys, both positive and negative. But the novelty quickly disappears for Archer, forced to vacation after a heated exchange with a Vulcan official. Also, Trip accompanies T'Pol to Vulcan, where he meets her mother, T'Les, but when T'Pol reconsiders marriage to her former fiance, Koss, Trip questions their relationship. The Xindi scare causes increased violent incidents against alien species on Earth, and Reed worries about Phlox's safety.
When genetically engineered humans left over from the Eugenics Wars hijack a Klingon ship, the Klingons threaten war with Earth. Archer enlists the criminal Dr. Arik Soong, the Augments' creator and "father," to help hunt them down.
Cold Station 12 is a medical research facility where hundreds of genetically enhanced embryos left over from the Eugenics Wars are still stored. Arik Soong leads his band of Augments to the scientific outpost, intending to retrieve the embryos, bring them to life, and create a superhuman army of Augments. On the raid, Soong realizes just how ruthless his "children" have become and threatens to release the deadly pathogens stored on-site if anyone interferes.
The Enterprise crew cautiously pursues Dr. Arik Soong and his superhuman Augments across hostile Klingon space toward a hidden planet where he intends to raise his Augment army. But in defiance of their "father" Soong, Malik devises a heinous plot to use a bioweapon against a Klingon colony planet, undoubtedly leading to interstellar war, to safeguard the Augments from Enterprise and further Starfleet interference. Malik's rash proposal leads to a rift with Soong.
The crew joins forces with Vulcan authorities to investigate a deadly bombing of Earth's embassy, which may be the work of a sect devoted to the logical teachings of Surak, the father of Vulcan philosophy.
The Syrranites subject Archer to a potentially lethal mind-meld after learning that information about Surak was placed in his head. Meanwhile, Vulcan officials plot the dissidents' destruction.
As Vulcan prepares for war, V'Las sends a commando team to eliminate Archer, T'Pol and T'Pau, while Soval risks his sanity to warn the Andorians of the impending attack.
Emory Erickson, the inventor of the transporter, boards the Enterprise to test new transporter upgrades. He also enlists Archer's help with a risky experiment resulting in a crew member's death. This forces Emory to reveal the real purpose of his test, searching for and retrieving his lost son.
Two non-corporeal Organians possess the bodies of various crew members to observe humanity's reaction to tragedy. The curious beings study the response of the Enterprise crew to a fatal silicon-based viral infection contracted by Trip and Hoshi during an away mission. Phlox works feverishly for a cure. Will the "advanced" aliens learn anything about human empathy and compassion?
While escorting a Tellarite ambassador to the neutral planet Babel for a peace conference with the Andorians, the Enterprise is attacked after answering a distress call from Shran. A secret Romulan vessel attacks ships on all sides, trying to halt any chance for peace.
Archer tries to unify the Andorians, Tellarites, and Vulcans in a plan to capture a remote-controlled Romulan marauder ship threatening to destabilize the region. But, a desire for vengeance interferes with Archer's attempts to ally Shran and the Tellarites, where Archer and Shran fight to the death, almost. Trip and Reed probe the inner workings of the unmanned Romulan warship and must outwit their captors to escape.
Archer and the crew try to prevent the Romulans from starting an intergalactic war. He visits Shran's icy homeworld to find an Andorian subspecies called the Aenar to determine their connection to the marauder destroying ships in the region. The Aenar are telepaths who could gain control of the Romulan drone vessels.
Enterprise visits Earth for the launch of its sister vessel Columbia, where Trip prepares for her maiden voyage as her new chief engineer. Meanwhile, Klingons kidnap Phlox and force him to help them find a cure for a mutated virus that threatens their species.
With Columbia's help, the Enterprise crew grapples with the sabotage left by Klingon Augments as they pursue the truth behind Dr. Phlox's kidnapping. Trip rejoins Enterprise on a desperate mission to rejuvenate her warp drive. Then both ships head deep into Klingon space to find Dr. Phlox. Antaak convinces Phlox to cooperate with the Klingons and help find a cure for the mutated virus ravaging one of their outposts.
As a gift for negotiating a deal with the Orion Syndicate, an Orion pirate persuades Archer to accept three alluring Orion slave women. But the captain's good-faith gesture has terrible results when the trio wreaks havoc within the ship, seducing all the men on board.
An amoral, imperialistic version of the Enterprise crew exists in a dark alternate universe. Commander Archer of the Terran Empire Enterprise mutinies against Captain Forrest to investigate an anomaly in Tholian space and capture a future Earth ship. The Star Trek episodes "Mirror, Mirror" and "The Tholian Web" inspire this mirror-universe tale.
In the mirror universe, power-hungry Archer and the crew use the 23rd-century Defiant to thwart a Tholian attack and its advanced weaponry to put down a rebellion setting their sights on seizing control of all of Earth's Terran Empire. But first, he must rid the ship of a deadly Gorn stowaway.
Archer and the crew are on Earth for a historic conference at Starfleet Headquarters to establish an interplanetary coalition. But the plans are menaced by a fanatical xenophobe, John Frederick Paxton. He leads Terra Prime, an underground Human isolationist movement plotting against the government and threatening to undermine the talks. This radical faction opposes the increasing number and influence of aliens on Earth and advocates expelling all non-Humans from Earth and the rest of the Sol system.
Determined to scorch Starfleet Command in San Francisco if Earth refuses to abolish a proposed interplanetary alliance and make all aliens leave Earth immediately, Paxton blackmails Trip into modifying his doomsday weapon, the Verteron array on Mars. Archer and a handpicked team infiltrate Terra Prime's Mars headquarters to stop Paxton. Hoshi takes command of Enterprise as a traitor lurks within the crew. Elsewhere, the origin of Trip and T'Pol's child is revealed.
Commander Riker interacts with Archer's crew in a hologram of their final mission as he deals with a dark secret from his past. Six years after the Terra Prime incident, an emotional Captain Archer and the crew return to Earth to decommission Enterprise and sign the charter for the Federation, the new alliance of planets they helped forge. Enroute, Archer agrees to help his old ally Shran retrieve his daughter as the captain prepares a speech to celebrate the Federation's establishment.