With help from Xindi allies, the Enterprise crew attempts to stop the arming of the Weapon aimed toward Earth.

Starfleet orders Enterprise to return home when the crew seemingly causes the destruction of an alien planet. However, a visit from Crewman Daniels leads Archer to believe that this disaster was the plot of one of the factions from the temporal cold war.

Archer tries to unify the Andorians, Tellarites and Vulcans in a plan to capture a marauder ship threatening to destabilize the region.

Archer puts his life on the line in a risky gambit to intercept the Xindi superweapon and disarm it from within.

The remnants of an alien ship and two frozen cybernetic bodies are uncovered in the arctic by a research team. These aliens soon thaw out and flee Earth, taking the research team with them. Starfleet orders Enterprise to find them, but the crew aren't prepared for just how dangerous these aliens really are.

After Archer and Trip become curious about a visit she made to a Pennsylvania mining town called Carbon Creek, T'Pol explains to them that Vulcans actually had their first contact with humans in 1957. That year, a Vulcan ship crashed on Earth and three crew members survived, including T'Pol's great grandmother. They pose as humans in Carbon Creek and take on jobs while waiting for rescue and soon find themselves becoming more involved with the town's residents.

An alien race known as the Xindi launch an attack on Earth, causing great casualties and massive damage. As Enterprise heads back home, an unlikely source informs Archer about the Xindi and that their next attack will destroy Earth.

An Andorian ship led by Commander Shran arrives in the Delphic Expanse to help Enterprise hone in on the Xindi super-weapon.

Archer and Hoshi stand before the Xindi Council as T'Pol and Reed lead a team into the heart of a Sphere.

Archer, T'Pol and T'Pau attempt to bring the Kir'Shara — an artifact believed to contain Surak's original writings — to the Vulcan capital, as the NX-01 gets involved in a Vulcan-Andorian military clash.

Archer finds himself face-to-face with Degra, the designer of the Xindi superweapon, and tries to get him to reveal its location.

Archer sets out on a suicide mission to destroy the Xindi superweapon as Enterprise faces a brutal attack.

Suffering from damage inflicted in the Romulan minefield and unable to complete repairs on their own, Archer orders a distress call to be put out. A response leads Enterprise to a repair station, which surprisingly has no crew aboard it and is run by computer. Repairs on Enterprise are carried out quite efficiently and quickly, though the price for all this is much higher than the crew could've guessed.

Enterprise journeys to Babel with a Tellarite ambassador on board for peace talks with the Andorians, when a distress call from Shran is received.

Enterprise is sent to the planet Mazar to pick up a Vulcan ambassador who has been expelled for misconduct.

A spatial distortion leaves Archer unable to form any new long-term memories. Years in the future, he wakes up one morning and is stunned to learn the outcome of the human-Xindi conflict.

Daniels and Archer must find a way back to the 22nd century in order to make sure history plays out as it should. Meanwhile, on board Enterprise, the Suliban have taken over the ship, but Reed, Trip, and T'Pol formulate a plan to eject the aliens.

Archer 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 Enterprise crew find a small craft drifting in space and are surprised to find it contains a human corpse. More questions arise when the Suliban and Tholians make claims to the craft.

Earth's embassy on Vulcan is bombed, and the ensuing investigation puts Archer and T'Pol on the trail of a Vulcan religious faction hiding in a treacherous desert.

Archer and T'Pol encounter the Syrrannites, a radical group hiding in the Vulcan desert, while the NX-01 crew contends with Vulcan power ploys.

Non corporeal aliens study the Enterprise crew as they respond to a fatal viral infection brought on board from an away mission.

A human isolationist leader threatens to destroy Starfleet Command unless all aliens leave Earth immediately.

Both the Vulcans and the Andorians make a claim to a small planet and military conflict soon erupts. As the fighting goes on, the Vulcans announce they are willing to discuss cease fire terms. However, Imperial Guard officer Shran believes only Captain Archer can be trusted to mediate the situation, which drags the Enterprise crew into the tense situation.

An attempt to use a Xindi subspace corridor leads the Enterprise crew to a bizarre encounter with their own descendants.

When Trip suffers a catastrophic injury, his only hope for survival is a transplant from a "mimetic symbiont" which Phlox grows from one of his exotic creatures.

The crew discovers a new planet with two races, one in desperate need of medical and scientific assistance. In the course of trying to help, Dr. Phlox recalls his own Denobulan past to address the ethical dilemmas that arise in the present.

Two high-ranking Xindi offer to stop the launch of their superweapon if Archer can prove they've been manipulated. Meanwhile, the crew mourns their lost mates.

With Columbia's help, the Enterprise crew grapples with sabotage to their ship as they pursue the truth behind the kidnapping of Phlox.

On a mission to investigate an abandoned Xindi vessel on a jungle planet, Archer, Reed and Hoshi succumb to a virus that mutates them into a primal life form.

Archer spends a night in sickbay with Dr. Phlox after Porthos contracts a deadly virus on the Kreetassan homeworld. Crew members suspect Archer's increased stress level is due to Porthos' illness, but Dr. Phlox suspects it has to do with Archer's repressed sexual tension.

The inventor of the transporter, Emory Erickson, comes aboard Enterprise for a risky experiment.

While exploring an uncharted planet, Enterprise crew members encounter a group of aliens who are hunting down indigenous creatures for recreation. During their exploration, Archer is mesmerized by visions of an elusive, yet familiar woman who needs his help.

Trip boards an alien cargo vessel to help repair a stasis pod, which holds a beautiful woman in suspended animation. When the woman accidentally wakes up, she reveals she's not a passenger, but a prisoner.

The Enterprise crew is dispatched by Starfleet Command to assist Fortunate, a human freight vessel that has been attacked by Nausicaan pirates. On arriving, they are surprised to find that Fortunate's crew is resistant to Archer's efforts to help them and determined to seek revenge against their attackers, no matter the repercussions.

A strange, alien creature comes aboard Enterprise, and captures several crew members in its cocoon-like web. With her crewmates' lives in jeopardy, Hoshi faces her biggest challenge yet, in trying to communicate with the lifeform, in order to return it to its home planet.

Archer goes to extreme lengths to save an abandoned nest of Xindi-Insectoid eggs ready to hatch.

Archer sends an away team to a habitable, luscious planet for observation. But when a storm occurs, the team begins to experience paranoid delusions.

Hoshi experiences her first transporter experience and strange aftereffects lead her to believe she wasn't reassembled correctly.

Mayweather discovers his father has died and that things on his old home, the E.C.S. Horizon, have greatly changed.

The Enterprise crew alters course to investigate the mystery of Terra Nova, a legendary Earth colony whose inhabitants mysteriously disappeared decades ago. But when they arrive, they confront descendents of the colonists who have become more alien than Archer could ever have imagined.

Six years in the future, an emotional Captain Archer and the crew return to Earth to face the decommission of Enterprise and signing of the Federation charter.

Archer and Tucker are arrested and placed on a prisoner transport heading for a penal colony, Canamar. They won't have a chance to correct this error, as one of the inmates plots a takeover of the ship.

In need of fuel, the Enterprise arrives at a Quonset mining colony for deuterium supplies. They discover that Klingons are forcing the colonists to give up all their deuterium. Archer and the rest of the crew work to train the colonists so they can fight back against the Klingons.

Archer, Mayweather and T'Pol travel to an arctic world to apprehend a fugitive, when T'Pol is contacted by Vulcan High Command. The mission takes a dangerous turn when T'Pol begins having flashbacks that suggest the events she remembers about a former mission may not accurately relate to what happened.

Religious zealots hijack Enterprise to use it as a weapon against the enemies of their faith.

Enterprise encounters a group of Vulcan civilians who have split off from the normal way of Vulcan life in an effort to explore their emotions. T'Pol is disturbed by the new visitors and warns the Captain that all attempts in the past to integrate Vulcan emotions into their lives has proven disastrous. Meanwhile, a message from Admiral Forrest leaves the Captain with the difficult task of trying to convince one of the visiting Vulcans to call home to speak with his dying father.

The NX-01 gets closer to a showdown with the Xindi when Captain Archer takes on an enigmatic passenger: a beautiful slave named Rajiin.

Archer, Hoshi, Travis, Malcolm and Trip have decidedly different experiences during shore leave on Risa. Meanwhile, on Enterprise, Phlox enters his annual hibernation cycle.

A powerful telepath makes contact with Hoshi and offers to help Enterprise find the Xindi ... for a price.

As a gift for negotiating with the Orion Syndicate, Captain Archer receives three Orion Slave Girls.

The Enterprise crew makes first contact with the Vissians, a species with three genders. Trip meets one of the species' third gender, known as Cogenitor, and learns how badly Vissians treat all Cogenitors. Trip attempts to help the Cogenitor, even though it interferes with Vissian culture.

Captain Archer wants to convert curiosity into deeds and decides to enter a ship floating in space. Hoshi has trouble adjusting to life on Enterprise.

Noncorporeal aliens possess the bodies of the Enterprise crew.

Archer learns the Klingons have put a price on his head when he is captured by a Tellarite bounty hunter. As Enterprise pursues, a virus causes T'Pol to go into premature Pon Farr.

When Archer and Trip are invited to a desert-like planet by an alien leader, they discover he is a terrorist who has lured them there under false pretences. Meanwhile, T'Pol, while in command, faces a tough decision when she cannot locate Archer and Trip in the desert.

While exploring a crashed vessel on a desolate planet, the Enterprise crew is haunted by some ghostly figures, and they encounter an alien race that has survived despite insurmountable odds. Trip helps repair their derelict vessel and is befriended by Liana, an attractive humanoid alien who develops feelings for him.

Archer and Reed return to a pre-warp society, that is on the verge of war, to recover a lost communicator from an undercover survey mission.