Do-hyun is a dedicated English major who enjoys his college life. One day, his professor asks him to help out a newly transferred student undergoing psychological treatment. Through this, he meets Professor Choi, a hypnotherapist. He undergoes a round of hypnosis himself, and wakes up to visions of unknown memories. Around him, his friends also begin to hallucinate strange events and witness mysterious incidents. As his nightmares grow more frequent and more terrifying, Do-hyun and his friends start to question Professor Choi`s intentions with them, and wonder if the truth lies within their newly-discovered unknown memories.