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.

Derek and Sarah must outwit Cromartie after he kidnaps Charley's wife, and they must weigh the consequences in rescuing her. Meanwhile, John finds himself unable to choose between Cameron and Riley.

A software glitch causes Cameron to forget who she is. She goes missing from the Connors and is taken in by a street kid named Jody. Cameron and Jody end up at a halfway house where Cameron meets with a social worker who uncovers some of Cameron’s distant memories. Meanwhile, Catherine Weaver meets with Agent Ellison to discuss his future at Zeira Corp, and Ellison does some digging into Weaver’s past.

The Connors find themselves on high alert and in odd company after their house is robbed. A Terminator terrorizes Ellison, while another gets dangerously close to John Connor. Derek and Jesse continue to get reacquainted.

As the Connors prepare to move, they find out that Riley is dead, and Sarah begins to doubt Cameron's motives. Jesse flashes back to a submarine mission in the future, and John Henry plays hide and seek with Catherine Weaver's daughter.