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.

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.

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.

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.