Inspired by the true story of the greatest security breach in US history.
When Eric O'Neill (Ryan Phillippe), a young agent-in-training, is promoted out of his low-level surveillance job and into the headquarters of the FBI, his dream of becoming a full-fledged agent is on the verge of becoming a reality.
Even more impressive, O'Neill is selected to work for renowned operative Robert Hanssen (Chris Cooper) within "information assurance," a new division created to protect all classified FBI intelligence. His enthusiasm, however, quickly turns to anxiety as O'Neill is confronted with the true reason behind his unexpected promotion. Hanssen is the sole subject of a long-term, top-secret investigation; he is a suspected mole who has become extremely dangerous by the sheer global import of the information he is protecting.
The Bureau asks O'Neill to use Hanssen's growing trust of the apprentice to slowly draw the traitor out of deep cover. Now engaged in a lethal game of spy-versus-spy, O'Neill finds himself fighting to bring down Hanssen before the treacherous double agent can destroy him, his family and the nation they are both sworn to serve.