Two rival detectives with different methods try to solve the murder of a missing girl after discovering her mutilated body in the tidelands of Incheon.

Hwang Shi-Mok had brain surgery when he was a child, which caused him to lack emotion. Now, Hwang Shi-Mok works as a prosecutor. He is rational, but cold and lonely. He is also one of the only prosecutors not involved in corruption. One day, a dead body is thrown in front of him. He meets Police Lieutenant Han Yeo-Jin at a murder crime scene. They work together to eradicate corruption at the prosecutor’s office and solve a serial murder case.

A desperate father who tries to save his daughter and a man who tries to save his wife. In their desperate efforts to save their beloved, the day repeats in endless loop, and two men realizes that there’s third man who keeps murdering their beloved out of vengeance.