When US Marine Sergeant Nicholas Brody is rescued after being help captive in Afghanistan, CIA operations officer Carrie Mathison suspects that Al Qaeda have enlisted him as a sleeper agent.

Brody continues to struggle with life at home with his family. He suffers from post-traumatic stress. Carrie watches the footage of life in Brody's home closely, tries to understand what's going on in his mind, and concludes he's still struggling with the fact that he's become a terrorist. She gets a lucky break when an undercover CIA agent passes on a new piece of electronic evidence to her.

The FBI mole in the Prince's entourage, Lynn, is assassinated. Meanwhile, the Brody family prepares for an interview at their home, while father and daughter get closer, and Agent Carrie Mathison witnesses awkward intimate moments of the Brody couple on the surveillance cam.

Brody continues to have hallucinations, some of them of Abu Nazir himself. Carrie sees his stunned reactions on the surveillance cameras, but doesn't know what's causing them. Questions are being asked in high places about Brody's mental stability, and the Vice President sends his closest adviser to check him out.

Afzal Hamid, the lone surviving terrorist from the compound in Afghanistan from where Brody was rescued, has been captured. Estes wants Saul and Carrie to find out everything he knows about Abu Nazir's plans to attack the US, but there's a catch: Estes wants Brody to help with the interrogation, noting that he's in a unique position due to his previous history with Hamid.

Reeling after losing key players in Nazir's plot against America, the CIA orders polygraphs on everyone who came in contact with them, including Brody, which Carrie sees as an opportunity to finally learn the truth.