A man lost a precious person because of a serial killer. He crosses over into a different world to figure out the truth behind her death. Seo Do-Won is a detective and he is enthusiastic at his job. Han Seo-Kyung is a prosecutor with an honest personality. Lee Jung-Min is a member of a scientific investigation unit. She is Seo Do-Won’s childhood friend and also his first love. She supports Seo Do-Won.