Erica Shepherd, once a highly skilled CIA agent, has become infamous as America’s most notorious traitor and is now serving a life sentence in a Supermax prison. Despite his deep reservations, FBI Agent Will Keaton finds himself with no other options and seeks Shepherd’s assistance to capture a highly dangerous and elusive criminal she is intimately familiar with. Although Shepherd and Keaton have distinct reasons for wanting to bring this adversary to justice, they both understand that to apprehend a spy, they must adopt the mindset of one.