In a callback to T2, Cameron, dressed as a L.A. cop, breaks into a power plant, shutting down some of Los Angeles's electricity. She then goes to LAPD, searching the evidence locker for the Terminator hand that Ellison found in the aftermath of their rescuing Derek; the evidence log says that Ellison has the hand with him. When Cameron reports back to Sarah and John, Sarah sends John off to school and Cameron back out to search for Victor, Andy Goode's partner, whom they think stole the Turk.
Ellison also has Sarah's file at home with him, complete with videotaped sessions from her time in the mental hospital. The hand is in his freezer for safe-keeping. As he watches the tapes, hearing Sarah rant so committedly about the rise of the machines, it looks as though Ellison might be starting to believe what she says. Sometime later, when Ellison is out, Sarah breaks into his apartment [how does she know where he lives?] and sees her file. She takes one of the tapes with her.
It turns out that Victor's sister Maria is a ballet teacher so Cameron signs up for classes - any excuse to use Summer Glau's ballerina training, I guess. After class, a Russian thug stops by, looking for Victor.
John comes home from school to find Derek mobile and re-loading their guns. Derek starts badgering John about how he shouldn't trust Cameron, and he lets Sarah have it too when she gets back. As his mom and uncle have it out, John finds the tape Sarah liberated from Ellison's and watches it, using his headphones so his mom won't hear. His eyes fill with tears immediately. In the morning, John rushes out to school and Sarah quickly realizes that he watched the tape. She plays it: on it, she signs paperwork terminating her parental rights. But there's no time for regrets - she found the name of her shrink from the mental hospital at Ellison's apartment and if Ellison is going to talk to him, so is she.
Ellison is the first to track down Dr. Silverman, Sarah's former shrink. Silverman offers him tea, which is drugged; when Ellison comes to, Silverman has tied him to a chair and insists on slashing his leg so he can see that the agent is flesh and bone, not a machine. The doctor recalls the scene in T2 where Sarah broke out of the hospital with the aid of Arnold, fleeing the sleeker Terminator. He's a believer now (but also slightly nutso), although no one believes him because there's no proof. Ellison tells Silverman that he has proof - in a cooler in the back of his car.
When Cameron returns to the ballet studio, the Russian thug comes back too. Cameron kicks the crap out of him and tells Maria that she can help Victor. So Maria takes Cameron to her brother. She asks him about the Turk and he admits that he is in debt to the Russian mafia (or something similar) and sold the computer for the money. He gives her the name of the guy he sold it to; Cameron turns and walks out. As more Russian mobster burst in, Maria shrieks that Cameron was going to help them! But our girl just leaves as shots and screams echo down the hall.
Silverman goes out and retrieves the hand from Ellison's car, and then immediately sets out to burn his house down, with Ellison inside, so that Ellison doesn't get in the way of Sarah's mission. He walks out to find Sarah there. He is overjoyed to see her; she flattens him with one punch. When the fire bursts a window, she hears Ellison screaming for help. She goes inside the burning house, extends her hand to Ellison and drags him out. While he's still unconscious, she takes the hand and leaves the men behind.
That night, Sarah explains to her son that the day she signed those papers was the day she decided to break out of the mental hospital (coincidentally the day John broke in to save her) because she couldn't bear what she'd done in relinquishing her rights. "I will always find you," she murmurs, and John nods, saying "I'll always find you" back to her. They bond over burning the hand with thermite.
Previously on T:TSCC / next time on T:TSCC
11 minutes ago