When Carrie (Claire Danes), a CIA counter-terrorism agent, was on a mission in the Middle East, her source revealed a startling secret to her: a captured American soldier had defected and was now working for al-Qaeda, preparing to launch a terrorist attack in the United States. A few months later, the U.S. Marine Corps found Sergeant Nicholas Brody (Damian Lewis), who had been captured for nearly nine years, in Afghanistan based on intelligence. Brody, who returned home, was treated like a hero. At the same time, Carrie was transferred back to work in the country by the CIA, and was convinced that Brody was the defected soldier, so she secretly launched an investigation. Brody discovered that his wife Jessica (Morena Baccarin) had fallen in love with his friend, and he had a relationship with Carrie out of jealousy. Carrie fell in love with this man on the one hand, but still had doubts about him on the other. Did Brody defect? How will his relationship with Carrie develop?