The series is set around the life of Kim In-ha (Lee Byung-hun), an orphan taken in the care of a poor gambler uncle. In his childhood often hung out with his friends at the basement of a theater. In-ha befriends Choi Jung-won (Ji Sung), a perfect student and also the son of the theater owner. Min Su-yeon (Song Hye-kyo), the daughter of the projectionist at the theater, became orphaned when her father dies because he owes money to the wrong people. In-Ha and Jung-won come up with a plan to avenge the death of Su-yeon's father's death together, planning to set fire to a gangster's hideout, but instead it accidentally led to the killing of a gang leader. In-Ha is sentenced to seven years in prison while thanks to Jung-won's family connections, Jung-won avoids sentencing. As In-ha serves his sentence, Jung-won goes to the US to study and Su-yeon decides to become a nun. Seven years pass, and by pure chance, the three all end up working at the same casino. In-ha and Su-yeon fall in love, but due to the circumstances regarding the past fire incidence, In-ha and Su-yeon get separated. In-ha is forced to illegally immigrate to the US, finding a job as a Mafia hitman. With stroke of luck, he meets Su-yeon in the States and the two plan to get married. However, on the day of the marriage, In-ha suffers a near-fatal gunshot wound and is placed in a coma for 8 months. Su-yeon, unaware that In-ha is alive, due to Mafia secrecy, returns to Korea and lives in despair. In-ha is able to ...