After missing and presumed dead for eight years, Marine Sergeant Nicholas Brody is rescued in Iraq, and returns home to his family. But CIA agent Carrie Mathison suspects he might have been turned by his terrorist captors, and believes he could be part of a plan to attack America.

Carrie receives new evidence from an undercover agent and stays glued to the surveillance footage of Brody's home, which reveals a man struggling with his traumatic memories.

The political powers that be make big plans for national hero Brody, but his increasingly erratic behavior threatens his media darling status; Carrie grows desperate for evidence linking Brody with Abu Nazir, as Saul directs her to focus on Nazir's money trail.

Brody confronts the lone survivor among the insurgents that held him, leading Carrie to believe she may be proved right about Brody once and for all - but Brody's reunion with his captor surprises everyone; the agency is hot on the trail of the lovers who bought a house near the airport with funds from a stolen necklace.

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.

The relationship between Carrie and Brody becomes more complicated when they head into the countryside for the weekend, while Mike and Jessica face the fallout of the truth about their relationship, and Saul catches Aileen on the run to Mexico.

As Carrie and Saul reel from the news that Walker is alive, the intelligence community clashes on the best way to capture him; Brody learns a shocking truth about his captivity.

After his attempt to sever ties with Abu Nazir, Brody finds himself reliving his captivity and recommits to his mission; Carrie finds herself in the middle of a public relations nightmare on the heels of the mosque shooting.

Carrie and Saul identify Walker's contact in Washington but their target has diplomatic immunity; Brody is approached to run for a disgraced congressman's seat in the House of Representatives.

In the wake of the explosion, Saul finds Carrie hospitalized and manic, but realizes her chaotic theories have merit; before his congressional campaign begins, Brody takes his family on a weekend trip to Gettysburg, where he retrieves an important item.

While Carrie is near catatonic and confined to bed, Saul investigates the unsettling implications of her timeline; Walker secures a perch for his mission; Brody makes his final preparations for the Vice President's policy summit at the State Department.