After going missing for eight years Sgt. Nicholas Brody is found alive by Special Forces in Iraq. Everyone sees him as a hero except for CIA agent Carrie Mathison who was tipped off that an American soldier had been turned by Al Qaeda. Brody returns home to his family who have moved on without him and reunited awkwardly with them. Mathison illegally puts his home under surveillance and becomes obsessed with proving that he has been turned.
An undercover agent hands over new evidence to Carrie who is keeping an eye on the surveillance footage of Brody's home. Mike is pressured to get Brody into the public eye while Brody spends hours alone in his room. Carrie visits her sister to collect more medicine.
Lynne is given an expensive necklace by the Prince and grows increasingly anxious about being discovered. Carrie tries to help protect her but has no support herself. Dana is acting out against Jessica and Brody steps in to try and re-bond with her.
Three weeks have passed since Lynne's death and Carrie must remove the surveillance equipment. Brody is feeling more distant from his family and tetchy with Mike. His public appearences have gone well though and he is attracting political interest. As Carrie works the diamond necklace angle David asks another analyst to keep an eye on her. She can't take hers off Brody.
One of Brody's torturers is picked up in Pakistan and handed over to the CIA. Brody is brought in to assist Carrie and Saul as they interrogate him. Brody begs David to let him confront Hamid and show that he isn't broken. Meanwhile Saul's marriage is coming to an end.
Faisel and Aileen go on the run and it seems like their handlers are trying to kill them. Brody has to speak at Tom Walker's memorial service. Afterwards he gets into a fight with Mike. He calls Carrie from a bar and she goes and gets drunk with him. Meanwhile Carrie insists that everyone who came into contact with Hamid take a polygraph test.
Brody and Carrie head out to her cabin in the woods and get intimate. They both admit to being comfortable together and try to have a sober night together. The next morning she slips up and he works out that she has been watching him. He then answers all her questions before driving home. Meanwhile Saul picks up Aileen in Mexico and drives her across the US trying to convince her to make a deal with him.
The CIA and FBI work together to catch Tom Walker. Saul discovers that he calls his home to hear his wife and child talking on their voicemail. They set up a trace on the line and almost track him down. Brody reconnects with his family. He and Jessica attend a party where plans are in motion to groom him for political office. Saul's wife prepares to leave for India despite his protestations.
Carrie pushes the Imam at the mosque to reveal whether he knew Walker or not. His wife puts her in the direction of a Saudi diplomat. Brody is kidnapped and taken to a room where Nazir can talk to him by video monitor. We see flashbacks to three years before where Nazir asked Brody to teach his son Issa English. Walker remains at large, using the woods for target practise.
Saul and Carrie prepare to interrogate the Saudi Diplomat while Brody makes plans to become a Congressman. Jessica is understandably against the idea and so Brody asks Mike to talk to her for him. Al Zahrani agrees to arrange a meeting with Walker and Carrie has a team in place ready to catch him.
Carrie has been off her meds while in hospital and surprises Saul with her manic behaviour. Her sister and Saul keep watch on her as she colour codes her classified documents trying to track down Abu Nazir's movements. Meanwhile Brody takes his family to Gettysburg. He picks up an explosive vest and Dana becomes suspicious of his behaviour. Carrie calls Brody as he is the only one who knows about Nazir's movements.
Brody says goodbye to his family, puts on his vest and heads out to the Vice President's press conference. Carrie is suffering from depression but gets Virgil to drive her there too. Walker sets up his rifle in a nearby apartment and takes shots at Elizabeth and others which means that Brody is rushed into a secure room with the Vice President and his supporters. He tries to flip the switch but it fails. Carrie goes to his home and asks Dana to call him and talk him out of doing it.