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.

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.