A mission to steal an ancient sketch pits Syd against her sworn nemesis, a Russian agent who's after the same target. But when the container holding the painting proves impenetrable, the two foes are forced to team up to satisfy their respective agencies. Meanwhile, Will begins to notice something very fishy about Danny's murder; and Francie frets over her guy's possible infidelity.

While helping Shepard escape from the asylum in Bucharest, Sydney discovers the shocking connection he has with her past. Meanwhile, after tracking the computer virus secretly planted by the CIA, Sloane is confronted by Alliance representative Alain Christophe, who suggests that one or more moles may have infiltrated SD-6. Will continues to investigate the woman claiming to be Danny's mistress and Sydney finds out the truth about her father's involvement in her mother's death 20 years earlier.

Sydney must undergo an extensive lie detector test to satisfy Sloane's frantic search for the SD-6 mole. Meanwhile, with nemesis Anna Espinosa following her every move, Sydney seeks out the connection that a device may have to the 500-year-old prophetic Rambaldi sketch. The mystery of Kate Jones deepens as Will continues to investigate Danny's death; and Sydney discovers that a keepsake from her mother Laura contains more disturbing connections into Jack's past alliances.

In order to save Will's life, Sydney and Vaughn must destroy a familiar looking Rambaldi device, while Jack makes a risky deal with Khasinau's representative, Mr. Sark. Meanwhile, the CIA believes that one of their own is a mole for "The Man"; the Alliance comes to a decision regarding the fate of Emily Sloane; Dixon's suspicions about Sydney intensify; and Sydney finds herself face-to-face with "The Man."