The FBI think they have a mole, so an investigation gets underway, and it puts Alex at war with his own ethics. Elsewhere, Victor devises a new method for staying on top of the O'Connors and Natalie makes a grievous error while searching for a lead.

Natalie relies on an outsider to obtain crucial info for her. Meanwhile, Sam and Alex make a dangerous move to detain an SVR source and Katya implores Alex to give her some breathing room with the task force, which leads Alex to confront Victor.