Jang Tae-san is a small-time gangster who has learned to survive with his fist and wits. He meets and falls in love with a college student, Seo In-hye, who sees a good heart and wounded soul underneath his tough exterior. When In-hye gets pregnant, Tae-san prepares to leave the gangster organization to start a life with her. But he is blackmailed by the gang boss, Moon Il-seok, who wants Tae-san to be his fall guy for an assault charge and go to prison in his place; Il-seok threatens to kill In-hye if Tae-san refuses. So Tae-san tells In-hye to get an abortion and cruelly breaks up with her, then goes off to prison for several years.
Eight years later, Tae-san is running a small pawnshop. One day, In-hye unexpectedly pays him a visit and tells him that she cut ties with her disapproving family and had the baby after all. But her daughter Soo-jin has been diagnosed with leukemia and needs a bone marrow transplant. Since she isn't a match, that leaves Tae-san. Reeling from the discovery that he's a father and wanting to do something good for once in his meaningless life, Tae-san agrees to the undergo the surgery, which is scheduled to take place in two weeks. But he becomes embroiled in political intrigue when Il-seok conspires with a corrupt politician Jo Seo-hee to frame Tae-san for the murder of an undercover agent, who had infiltrated the gang under the orders of prosecutor Park Jae-kyung. Tae-san is arrested by detective Im Seung-woo, who happens to be In-hye's current fiance. While being transported, the police car he's in gets into an accident and Tae-san escapes. Now a fugitive, he is hunted by both the police and an assassin, and what ensues is two weeks of his desperate struggle to save his life and his daughter's.
Orphaned at a young age when his father left and his mother committed suicide, Tae-san became a small-time gangster. After getting falsely accused of murder and learning that he has a daughter with leukemia, Tae-san spends the next two weeks in a life-or-death struggle to save himself and the girl.
She is the first love Tae-san can't forget, and unbeknownst to him, In-hye raised their daughter Soo-jin as a single mother for eight years. After Soo-jin's leukemia diagnosis, In-hye and Tae-san embark on a race against the clock to save their daughter's life.