When the Enterprise comes in contact with an alien vessel transporting stargazers to observe a spectacular stellar event, Archer invites them aboard the ship not realizing that Silik, a Suliban enemy, is among them. Archer quickly realizes that Silik is engaged in a nefarious time-travelling mission and must stop him before he can tamper with the course of history.

When militants take over a world, the Enterprise crew move to evacuate Denobulan geologists that are deep underground. Meanwhile, Phlox has to save a dying Antaran that refuses treatment due to the history of their races.

A spatial distortion leaves Archer unable to form any new long-term memories. Years in the future, he wakes up one morning and is stunned to learn the outcome of the human-Xindi conflict.

With help from Xindi allies, the Enterprise crew attempts to stop the arming of the Weapon aimed toward Earth.