Flashing in and out of consciousness, fighting for his life Derek Reese recalls his future life battling the machines in 2027. Meanwhile, Sarah tries to explain the past to Charley.

Sarah and Cameron investigate a nuclear power plant; John grows less enthusiastic about academics but flourishes socially with the help of a new friend; Catherine Weaver gets another piece of the puzzle for her pet project.

Fate is changed forever on the explosive season finale episode! The Connors come face-to-face with Weaver in a confrontation that shakes John to the core and changes his reality. Nothing will be the same.