South Korea, 1993. An agent of the National Intelligence Service is sent to Beijing to infiltrate a group of North Korean officials with the ultimate goal of obtaining information about their nuclear program.
Eric O'Neill, a low-level surveillance expert with the FBI, believes he is accomplishing his dream of becoming a full-fledged agent, with his unexpected promotion and assignment to clerk for Robert Hanssen, a renowned senior agent with 25 years in the FBI. However, he soon learns the reason for his promotion is to gain Hanssen's trust and find proof that he is a traitor to the country. Determined to draw the suspected double-agent out of deep cover, O'Neill finds himself in a lethal game of spy vs. spy, where nothing is as it seems.
When the president of Russia suddenly dies, a man whose politics are virtually unknown succeeds him. The change in political leaders sparks paranoia among American CIA officials, so CIA director Bill Cabot recruits a young analyst to supply insight and advice on the situation. Then the unthinkable happens: a nuclear bomb explodes in a U.S. city, and America is quick to blame the Russians.