When former Marine Sergeant Nicholas Brody is rescued after being held in captivity for eight years in Afghanistan, CIA operations officer Carrie Mathison believes he has been turned into a sleeper agent by Al-Qaeda after previously receiving intel that an American prisoner had been turned.
In Bagdad, Carrie Mathison a terrorist named Hasan Ibrahim in order to find out more information about a suspected attack on U.S. soil by a terrorist named Abu Nazir. She meets Hasan and is able coerce him into giving him information She is displeased to hear that an American POW has been "turned." Sometime later, she learns that a POW named Nicholas Brody had freed from terrorist captivity and she suspect he may be the POW that had been turned. Unable to get clearance from Saul for surveillance of Brody, Carrie begins spying on Brody illegally. When Nicholas Brody returns home, he is greeted by his family. However, he quickly learns that things have changed since he left. His wife, Jessica, for example, has gotten into a relationship with his best friend Mike Faber.
Nick Brody is called in for routine questioning. Carrie, who calls in a favor from Saul Berenson, is able to find a place at the meeting. Intent on finding guilt over whether Brody is a terrorist, she begins asking him about whether he had seen Abu Nazir, who was Brody's partner. Brody lies by telling her he did no meet him. On the way home, Nick takes a detour to visit Tom Walker's widow in the park. He tells Tom's wife that he had been forced to watch Tom being beaten to death. When Carrie returns home, her secret operation is discovered by Saul. Worried about her job, Carrie tries to seduce Saul, but it only angers him. Depressed, Carrie decides to go to a bar. Watching the jazz band at the bar, she has an epiphany. Looking at news footage from earlier, Carrie catches Brody doing strange gestures on screen.
She shows Saul her findings and tells him Brody could be signaling a terrorist group. Saul allows her operation to go on quietly. In the morning, Brody goes out for a jog. When he stands in front of the U.S. Capitol building, he has a flashback where he beat Tom Walker to death.