While Enterprise is surveying a black hole in a trinary star system, the stellar phenomenon causes strange effects on the crew.

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.

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.

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 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.

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.

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.

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.

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.