Li Jen-yao, 25-year-old, turns himself in for a series of cold-blooded murders and admits to being the serial Rainstorm Killer, who once terrorized his high school classmates. While he reveals the grisly details of his crimes, he never discloses his motive. In prison, he grants his first-ever interview to Chou Pin-yu, only for her to become entangled in unsettling dreams of both the killer and a mysterious girl in uniform. As dreams and reality intertwine, long-buried secrets of love, hatred, guilt, and redemption resurface.