Chul-soo is a man with an intellectual disability. One day, Chul-soo finds out that a young girl, Saet-byul, who is in hospital is his daughter. And soon, Saet-byul sneaks out of the hospital and travels by herself to a faraway city for her friend's birthday. As Chul-soo accompanies Saet-byul's journey, friendship develops between the two.

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.