A reverse comedy that tells the story of a perfectionist assassin who falls and hits his head in a sauna, giving him amnesia. When a down-and-out actor switches locker keys with him, they switch lives until the hit-man, who soon becomes an action hero on TV, starts to remember things.

Take a nostalgic trip back to the late 1980s through the lives of five families and their five teenage kids living in a small neighborhood in Seoul.

HA Yoon-ju becomes the newest member to a unit within the Korean Police Forces Special Crime Department that specializes in surveillance activities on high profile criminals. She teams up with HWANG Sang-Jun, the veteran leader of the unit, and tries to track down James who is the cold-hearted leader of an armed criminal organization.