In the mid-22nd century, the Earth ship Enterprise is launched under the command of Captain Jonathan Archer. When the crew rescues an alien from a crashed spaceship, Earth gets its first look at the alien's race - the Klingons. Archer and his crew must walk a fine line as they attempt to communicate with the Klingon pilot, whose language is completely unknown, and whose homeworld wants him back. Is this the beginning of friendship...or interstellar war?

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.

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

After helping to repair the warp drive on board of a Xyrillian ship, Trip notices a strange bulging on his arm.

Enterprise tries to find out what happened on Terra Nova, the first colonization attempt outside Earth's solar system.

Enterprise discovers a comet which contains the very rare element eisilium. Then unexpectedly a Vulcan ship arrives. Captain Vanik tells they're interested in human behavior.

Enterprise is sent to help the freighter Fortunate after an attack. However, its first officer, Ryan, is hiding something.

Enterprise has a group of aliens watching a stellar phenomenon on board. When the ship is miraculously saved from blowing up, crewman Daniels has an important message for Archer.

Phlox is asked to save the Valakians from annihilation by disease. However, he discovers something unusual about the Menk, another humanoid race on the planet.

Enterprise tries to rescue a Klingon ship from sinking into a gas giant.

Almost the entire crew is left unconscious when four Ferengi pirates raid Enterprise. A still conscious Trip is the only one who can get rid of them.

The crew of Enterprise searches for a seemingly abandoned ship on a desert planet.

A fibrous, web-like alien creature comes aboard the ship and several of the crew becomes entangled in it including Archer and Trip, and it seems Hoshi is the only one who can try to communicate with the creature.

Enterprise is for the second time on its way to Risa when yet again another urgent matter comes up: a distress call. It comes from a small vessel. The owner, Zobral, is extremely happy with the help from Enterprise and invites Captain Archer to his home world for a good meal and a game of Geskana. When Archer and Trip have landed on the desert planet, Enterprise gets a message from the Torothan Chancellor Trelit. He says Zobral isn't as nice a man as captain Archer thinks.

Enterprise discovers a mining colony of the Paraagans. The crew gets an invitation for a meeting on the surface and a shuttle pod tries to break through the atmosphere. All of a sudden just under the shuttle a giant explosion begins and scorches the earth beneath. All 3600 colonists are reported dead. After examination, Enterprise finds out plasma leaking from the pod's vents ignited tetrazine in the atmosphere. Lieutenant Reed, however, ensures he closed the plasma vents before the shuttle went of. After conversations with admiral Forrest of Starfleet Command, Captain Archer learns that Enterprise's mission is canceled and they must return home, not to return to space for another ten or twenty years. When the ship has altered course, crewman Daniels, a time traveler, pays a visit to captain Archer.

The safety of Enterprise rests on Reed's shoulders when the ship becomes trapped in a Romulan minefield and Romulan ships are closing in on them.

Enterprise seeks repairs from their encounters with the Romulans, where they stop at a desolate but idyllic repair station. But all is not what it seems when Mayweather is suddenly found dead.

Enterprise visits a colony with a deuterium trading post. But the people seem to be pretty unwilling to trade. Are they hiding something?

T'Pol must save the ship after the crew becomes obsessed with trivialities during the approach to a black hole.

After Hoshi uses the transporter to avoid running into a storm, she starts to feel very strange.

After receiving a warning about a radioactive storm approaching Enterprise, the crew is forced to take shelter in the ship's catwalk.

T'Pol is diagnosed with a possibly fatal neurological disease as a result of a mind meld. Meanwhile, one of Phlox's wives visits Enterprise and becomes very interested in Trip.

Archer and Trip are accused of smuggling and sent to the penal colony Canamar. While Enterprise manages to negotiate their release, a mutiny breaks out on the prison ship.

Enterprise is held captive by non-corporeal beings who claim to be explorers.

After Enterprise lends aid to a group of accused rebels, Captain Archer faces a tribunal and charges of conspiring against the Klingon Empire.

Mayweather temporarily leaves Enterprise to visit the cargo ship Horizon, where he was born and raised. Meanwhile, the Enterprise crew observes an unusual planetary event.

Enterprise encounters a hyper-giant star. While there, they make first contact with the Vissians, a technologically sophisticated race with three genders. While making quick friends, and eagerly learning about the advanced technology, Trip gets curious about the Vissians third gender, known as the Cogenitor, who is crucial in the Vissian reproductive process. Against the wishes of the Vissians, Trip befriends the Cogenitor and encourages it to defy its cultural boundaries, which the Vissians are made aware of, and are angered by.

An Arctic research team makes a startling find: cybernetic creatures - Borg - buried in the ice. When the revived aliens seize control of a spacecraft, it's up to Archer to keep them from contacting the Collective and threatening Earth.

After an attack by Osaarian pirates, Enterprise follows them to a mysterious sphere.

Enterprise helps an alien woman, Rajiin, seeking to escape her life as a sex slave. Once on board she uses her alien abilities to gather biometric data about humans and is recaptured by her employers, the Xindi council.

Hoshi Sato is contacted by a 400-year-old telepathic alien exiled on planet in the Expanse, shunned by his society because of his abilities. The alien offers to use his powers to help Enterprise find the Xindi and the weapon they are building, but only if Hoshi will stay with him while he works. She agrees to stay behind, while Enterprise confirms the Expanse has a second Sphere and is on its way to investigate.

Enterprise follows a lead and discovers a Xindi lab that refines Kemocite, the key ingredient in the weapon being built to destroy Earth. An away team of Archer, Reed and Hayes confront the lead researcher, Gralik Durr, who was employed by Degra to refine the Kemocite but was never told what it would be used for. When Gralik realizes it was his research that contributed to the 7 million deaths on Earth, he agrees to help Archer prevent further loss of life. Meanwhile, on Enterprise, Phlox and Tucker study the weapon they seized from the Xindi and find an organic component, a life-form serving as the rifle's power cell. Despite T'Pol's objection, Tucker tests the weapon.

Enterprise is taken over by religious zealots who want to use the ship in a war against heretics.

Enterprise has found the location of the testing site of the Xindi weapon and gets some rather unexpected help.

Archer and the Xindi 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.

While in command of Enterprise because the entire crew is in a coma, Dr. Phlox starts hearing some strange sounds.

Captain Archer has been returned to Enterprise by the Xindi council awaiting a hearing. But after a heavy attack by the Reptilians, Enterprise is stranded without a functional warp drive. They meet another ship in trouble because of space anomalies. The ship's captain isn't willing to trade in their warp coil and Archer must make a tough decision. Meanwhile T'Pol is having some strange sensations and can't control her emotions.

After a Klingon ship is attacked, it's discovered the imprisoned Dr. Soong's genetically enhanced humans are responsible. Archer takes him to prevent a war.

T'Pol and Archer confront the Syrrannites and meet T'Pau who denies the embassy bombing. Archer, who has Surak's essence, is asked to help. V'Las threatens Enterprise to make sure an attack on the Syrrannites isn't witnessed.

Dr. Emory Erickson comes aboard to supposedly conduct tests for subquantum transportation. However, he seems to have a different agenda.

The men of Enterprise fall under the seductive control of three Orion women. Trip is the only male member of the crew not to succumb to the women.

Set in the dark and oppressive Mirror Universe, Commander Archer leads a mutiny in a bold attempt to seize control of an advanced starship - a vessel from the future that may be the key to saving the Terran Empire.

In 2370, Commander William T. Riker is trying to clear his mind and relives the last mission of the first Enterprise on the holodeck.