Chiu and his best friend, Hung, invoke a saucer spirit (a Chinese equivalent of the Ouija board) in an attempt to find out the questions of an upcoming assessment, but they are interrupted halfway through the process and do not finish it properly. They desperately try to finish the process at Chiu's home but supernatural events take place, resulting in the death of Chiu's parents.
Eighteen years later, Chiu, who has been learning the art of exorcism from a master after the tragedy, meets Hung again. Hung has been suffering from severe PTSD in the last eighteen years. As Chiu tries to help his best friend overcome his condition, supernatural happenings take place, and they realize the the problem that started eighteen years ago may not have ended.