Orphaned at young age, abandoned by his uncle and later by his adoptive parents, Sang-doo’s life has been a succession of difficulties. At 27, he makes a living by seducing older women in order to support his daughter’s hospital fee. However, the love he has for his first love, Chae Eun-hwan, keeps him happy and optimistic. When he runs into Eun-hwan again, he decides to give another chance at his love and goes back to high school to be Eun-hwan’s student.

Haruto Narusawa, the president of a video game company, enjoys life in the affluent seaside town of Kamakura with his wife and daughter, who attends an elementary school. However, tragedy befalls this happy family when his daughter is kidnapped. Haruto must now face numerous hardships as he navigates through the complex web of human nature that begins to show its ugliness. The only way to save his beloved daughter is to take matters into his own hands without the police's involvement and, together with his wife, stand against the kidnappers. Can this family's story reach a happy ending? Or will theirs be a tragedy? This non-stop family suspense-thriller tests the bonds of a family facing life's worst nightmare.