After turning herself in to the CIA, Irina won't communicate with anyone - except her daughter. Sydney refuses to cooperate, until a mission goes awry and crucial information falls into the wrong hands. Now, against Jack's wishes, Sydney must face Irina and find out what She knows.

When a young CIA agent dies, suspicion immediately falls on her parter and lover, agent Jim Lennox. But after Sydney rescues Lennox from captivity, She trikes up an instant connection as they discover shared wounds - realizing They've both lost someone they love to the job. Yet even her judgment is thrown when Vaughn and Jack discover that Lennox was pursing a technology that allows people to change their appearance. Now Sydney must ask herself: is this the real Jim Lennox - or is his double?

When Sydney learns that Vaughn is under investigation for being a double agent, Jack and Irina forge an unlikely partnership in their attempt to get their daughter out of the CIA for good. Kendall learns that Sark and Sloane are attempting to get their hands on a Rambaldi manuscript detailing the works of the human heart, so he sends Jack and Irina to Bangkok to learn more, and then to Panama to capture Sloane. But Irina betrays Jack and escapes from custody... this time for real.

After escaping from Peyton and her henchmen, and learning she's on a freighter at sea, Sydney goes to the communications room and sends a message to APO routed through the CIA to her whereabouts. Unbeknownst to her, the message is intercepted by a mole at the CIA working for Prophet Five, although APO was able to obtain a piece of the transmission. Wanting to retrieve Sydney, the APO team, Rachel, Tom, Dixon, and Marshall attempt to break into a secured server room located at Langley with the goal of obtaining the remaining part of the transmission. Problems arise, however, when APO is forced to take the hard drive, which triggers an alarm. They manage to escape the situation thanks to former APO agent Eric Weiss who aids them in sneaking past the guards. Although the transmission on the hard drive is corrupted, APO is able to learn who corrupted it. Jack sets a meeting up with the division heads of the CIA and is quickly able to identify the mole. Meanwhile, Tom is revealed to have another agenda when he obtains information about a certain Allan Korman, who was a former German assassin now in a witness relocation program, and who murdered Tom's wife many years earlier.