Nobita saw a moon turned yellow last night and told his class about it but they think it's funny. Doraemon gives him the "History Explorers Club Badge" and discovers there's life on the moon. Until a new student changed him forever.

Gon, a Korean hitman bred in the United States where he works for a Chinese triad, usually flawless in taking out his targets, makes a terrible mistake in fulfilling a mission. Swamped by feelings of regret, Gon no longer wants to be a hitman, but, in order to tie up loose ends, his boss forces him to do another job in Korea.

His only friend called him 'the man from nowhere'... Taesik, a former special agent becomes a loner after losing his wife in a miserable accident and lives a bitter life running a pawnshop. He only has a few customers and a friend named Somi, a little girl next door. As Taesik spends more and more time with Somi, he gets attached to her. Then Somi is kidnapped by a gang, and as Taesik tries to save Somi by becoming deeply associated with the gang his mysterious past is revealed...