A human isolationist leader threatens to destroy Starfleet Command unless all aliens leave Earth immediately.
In the mirror universe, Commander Archer mutinies against Captain Forrest in order to capture a future Earth ship found in Tholian space.
With Columbia's help, Enterprise's crew grapples with sabotage to their ship as they pursue the truth behind the kidnapping of Phlox.
Archer tries to unify the Andorians, Tellarites and Vulcans in a plan to capture a marauder ship threatening to destabilize the region.
Enterprise journeys to Babel with a Tellarite ambassador on board for peace talks with the Andorians, when a distress call from Shran is received.
Archer, T'Pol and T'Pau attempt to take a sacred, but controversial artifact back to the Vulcan High Council, in hopes of settling an internal struggle going on among the Vulcan people. Meanwhile, Trip and Soval take Enterprise to Andoria to convince Shran to help them stop a war.
Enterprise returns to Earth to a hero's welcome, Archer is haunted by his experiences and actions in the Expanse. Meanwhile, realising that his home has been destroyed, Trip travels to Vulcan with T'Pol, where she faces a difficult situation.