Kim Soo-hyun stars as Ryu-han a North Korean sleeper agent in the
South. He infiltrates a small town. Over the course of the next two years
Ryu-han observers the town folk, earning their trust. He is soon joined by the
North’s elite spies, Hae-jin and Hae-rang who pose as a student and rock star
respectively. Ryu-han teaches his co-spies how to settle into the world of
South Korea and to become accustomed to their enemy. But the harmony of
the three is shattered when, after a political shift in the North, they receive a
new, deadly mission….