The episode begins with a wounded man appearing in an alley via a time travel bubble. The man runs away in fear.
In the church, Sarah and Derek talk about Cameron, about how they can no longer trust her. Cameron tells John that he did a dangerous thing by risking his life to save her, and that his decisions can no longer be trusted. Sarah stops by and tells him he needs some boring in his life and he should return to school. Cameron will stay with her and Derek.
At school, John looks around at his happy and laughing classmates with suspicion. A girl stops by and talks with him named Riley. She flirts with him which is just what he needs.
Sarah, Cameron and Derek start looking for a new place to live. Kacy, the lady who shows them the house is pregnant, and Cameron seems fascinated by her. As they settle in, the wounded time traveler crashes through the patio door. The man has a bar code tattoo on his forearm, indicating his status as a former Skynet prisoner. He gasps a warning about stopping someone called Greenway at a power plant at Serrano Point in two days, then expires. Derek proposes he handle it, but Sarah disagrees with his methods and insists on coming along.
Agent Ellison stops by the Dixon house and talks with Michelle. She found a gun in the house and is worried about her husband Charley. Charley tells her the truth about Sarah and John, and that Terminators are real. She is not happy and slaps him, then leaves the house. Ellison warns Charley that he needs to take his wife and leave.
As they surveil the power plant, Derek has a flashback of a battle at the power plant in the future. The resistance succeeds in taking the plant back from Skynet, and it becomes a key strategic holding. Sarah and Cameron get temporary jobs at the power plant based on their placement test scores and the fact that two janitors called in with emergencies.
Riley tells John her story and asks him about his wounds. He tells her he was in a car accident while he was trying to teach his sister how to drive. John invites her to see his new house with him. When they get there, they look for his new room and John is chagrined to find a room decorated for a child,
Cameron identifies Greenway as a safety engineer at the nuclear power plant and points him out to Sarah. He seems frazzled with the pressure of the plant coming online in 36 hours and the plant manager pressuring him to not delay the schedule.
Sarah finds Greenway after hours at a local tavern and joins him for a drink. She finds out that Greenway is a cancer survivor when she notices a scar on his arm. While she gets him talking, Cameron flirts with some of the local plant workers to glean information from them. Outside Derek breaks into Greenway's car to find anything about him. A local man smashes the window of Greenway's car. When Sarah, Cameron and Derek pool their knowledge they discover a conundrum. Greenway is concerned about a coolant pump issue. If he is right and the pump fails, the reactor could meltdown and contaminate half the state, Skynet wins. If he does stop the test and the plant gets shutdown because of the delay, then the resistance can't use the plant in the future and Skynet wins again.
When Sarah gets home and finds Riley there, she is upset with John. She tells him this is not the time, but he counters with, when is the time to live his life? Angrily, he takes Riley's hand and they go to his room where they commiserate about parents.
At the plant, Sarah notices the plant manager leave after getting a message on his cell phone and she follows him to a secure room. She uses a swipe card that Cameron made to gain entry and finds another room beyond that contains barrels of radioactive waste. The plant manager catches her and she tries a lame excuse about looking for the supply room. He tells her that since she is here, there is a hydraulic fluid leak that needs cleaned up so she should put on a radiation suit and get to it. She suits up and goes in but has a panic attack and quickly comes out of the room. Another worker uses a Geiger counter to measure her exposure and determines she has been “crapped up”, which is slang for being contaminated and she needs to have her entire body scrubbed clean. After undergoing the painful and embarrassing scrubbing, the plant manager tells her it was a mistake, that sometimes the scanners mess up, effectively putting her in her place for following him.
John wakes up in the morning to find Riley sitting there watching him, apparently having spent the night. She asks if he is going to make it to class and he says not today. She asks if she can call him sometime. He tells her okay, but that the first words out of her mouth need to be the date, day forst then the month. She asks why and he says that is because that is how it is.
As Charley and Michelle are preparing to leave, Ellison stops by and gives him a Bible to take with them. Charley asks whether Ellison is leaving or does God have a plan for him. Ellison say time will tell.
At the plant, a test is about to be performed and Sarah notices Greenway acting strangely and calls Derek, who is at Greenway's house. When she notices his arm no longer has the scar, she knows something is wrong. Derek discovers Greenway dead in his house, apparently a suicide. The fake Greenway approves the test and the reactor comes back online.
The fake Greenway leaves the control room and goes into the plant where he closes a valve, dropping water pressure to the coolant pumps. Sarah finds Cameron mopping the floor and tells him Greenway has been replaced by a Terminator. Cameron ignores her at first and finally tells Sarah she is thinking about what to do, surprising Sarah. Men come running out of the interior of the plant saying there is a problem with a turbine. Sarah tells Cameron to go fix it.
The Terminator returns to a panicked control room and tells everybody to remain calm, that everything is fine. One of the workers leaves to get help from the plant manager. When he gets to the control room, everyone is dead, and the Terminator sees Cameron via a monitor trying to repair his damage. He heads down to the plant floor and starts hand combat with Cameron. Derek arrives and tells Sarah they can't stop the meltdown and need to leave. Sarah refuses to listen and heads down to the plant floor, disarming a guard along the way. She ignores the radiation warning signs and enters the room where Cameron and the Terminator are battling. She opens fire on the Terminator which distracts it long enough for Cameron to throw it into a large electrical power grid which burns the skin from it and causes it to shutdown. Cameron then reopens the valve and stops the meltdown. Later, she disassembles the Terminator and stores his body parts in barrels marked for radioactive waste.
Later at home Cameron uses a Geiger counter to check Sarah's exposure and declares she is clean. Sarah worries that this is how she got the cancer that Cameron told her she died from in the other time line, but Cameron doesn't know for sure.
John gets a call from Riley, who correctly uses the date code he told her about. She tells him she is just practicing, but the call cheers him up.
While thinking outside, Sarah notices bloody hand prints leading into the basement. On the wall inside she finds messages, places and notes left behind from the wounded time traveler that died in her new home.
At the power plant, a press conference is underway with the speaker telling the reporters that the owners of the plant and six others have agreed to allow Automyte systems to install sophisticated computer monitoring systems in place of humans in the control rooms. The man leaves and after getting into his car, shape shifts into Catherine Weaver. Share this article with your friends