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

Tucker and Reed set out on a mission in a shuttlepod, as Enterprise is busy investigating an asteroid field. Disaster strikes while the pair are away, leaving the shuttlepod damaged and the warp drive inoperable. They manage to make it back to the rendezvous coordinates only to discover Enterprise was apparently destroyed when it crashed into an asteroid. With the ship seemingly no more, the pair are left abandoned in the middle of nowhere with only a few days of air remaining.

While exploring a planet, Archer and Mayweather 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 sharing a cell with some Suliban detainees who they believe may be wrongly imprisoned.

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.

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.

Enterprise visits a planet where an Interspecies Medical Exchange conference is being held. Dr. Phlox tries to obtain research on a terminal disease from the Vulcan contingency, without revealing T'Pol has been infected by it.

Noncorporeal aliens possess the bodies of the Enterprise crew.

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.

When Enterprise responds to a distress call from a Vulcan ship stranded in the Delphic Expanse, Archer and his boarding team are attacked by insane zombie-like Vulcans.

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

As Archer tries to unravel the mystery of a rescued alien, long-simmering feelings explode among his senior officers.

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

When genetic supermen left over from the Eugenics Wars hijack a Klingon ship, Archer must rely on their creator, the criminal Dr. Arik Soong, to help hunt them down.

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