While you were sleeping

Hong-Joo lives with her mother and helps her run a pork restaurant. Hong-Joo is haunted by seeing the future deaths of others in her dreams. What's worse is that she does not know when the deaths will happen, but she tries to stop her dreams from becoming reality. One night, Hong-Joo dreams about the death of her own mother.

Meanwhile, Jae-Chan is a rookie prosecutor. He meets Yoo-Beom at the prosecutors’ office. Yoo-Beom was Jae-Chan’s private tutor when Jae-Chan was a student, but an incident caused Jae-Chan to dislike him. Yoo-Beom was a prosecutor, but he now works as a lawyer. He takes on any case that brings him money.

Jae-Chan and his younger brother move to new house and they become neighbors with Hong-Joo. One night, Jae-Chan dreams that Yoo-Beom drives Hong-Joo's car and this leads to a chain of events including the death of Hong-Joo's mother and then Hong-Joo. When Jae-Chan senses that his dream is about to become real, he takes extreme action to stop it. Yoo-Beom becomes furious at Jae-Chan, but Hong-Joo hugs him and thanks him. Jae-Chan and Hong-Joo later work together to solve other cases.