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.

How can a mermaid from the Joseon era survive in modern-day Seoul? Shim Chung is a mermaid who finds herself transplanted to modern times. She is caught by Heo Joon Jae, a charming but cold con artist who is the doppelgänger for Kim Moon, the son of a nobleman from the Joseon Dynasty. But in the present time, Joon Jae works with Jo Nam Doo, a skilled conman who guides Joon Jae to become a genius scammer. But Joon Jae’s friend, Cha Shi Ah, who works as a researcher at KAIST, may be Chung’s only hope for surviving in her strange new world.

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.