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.

Joon-il, who was once a national team-level prospect, now just a coach at a local soccer class. He is on the verge of being fired for his old-fashioned mind and lazy coaching, and is about to get divorced. Joon-il is given a mission he can't refuse in exchange for a full-time job. It was the final round of the amateur futsal tournament of the "Cheolsoo Soccer Team." In a very short period of time, Joon-il had to transform President Kim, Mr. Choi, and Mr. Park who had no previous knowledge of the sport... Oh my futsal! With the dreams and livelihoods of grown-ups on the stake, "Sunday League" begins!

A comic book storekeeper, Dae-man, and the legendary homicide detective, Tae-su, who met on previous case quit their jobs to open a private detective agency.

During the Japanese colonial rule of Korea, while people are in despair, Jae-ho tries to raise morale by winning cycle championship. Bok-dong, who started cycling with Jae-ho just to make a forture, becomes a symbol of hope for Koreans by defeating Japanese cyclists.

In the 1990s, when Go gambling fever swept Korea, Gui-su loses everything because his father gambled obsessively until there was nothing left. Left all alone in the world, Gui-su meets a mentor and Go teacher, Il-do, and goes through vicious training to become the grandmaster of Go. He sets out for revenge on the world that destroyed his life, but soon finds himself chased by an unknown loner pursuing his own vendetta.