Moo Yeom is a detective. 20 years ago, he was a Buddhist monk, but he got into trouble with a man named Gap Dong. To cut ties with him and cut off whatever karma would arise from his involvement with Gap Dong, Moo Yeom became a detective. After the statute of limitations expired, Gap Dong appears once again. Moo Yeom sets out to catch him once and for all. ~~ Inspired by the "Hwaseong serial murder case".