Five medical students, including Chi Hon-wah, Leung Ka-lai, and Cha Chun-chung, studied synthetic blood in the hopes of achieving a medical breakthrough. During the experiment, Yeung Yiu-nam became violently insane and was subsequently killed and buried on campus by his friends. Years later, Chi still felt guilty about Yiu-nam's death and tried to make amends by looking after Yiu-nam's sister, Lee Hau-ling. Chi and Hau-ling became close, but Yiu-nam continued to haunt them after his body disappeared during an autopsy.