Jeongwoo has been unable to sleep for a while now - ever since a ghost started showing up at 3 am every morning, biting its nails. Upon seeing this ghost, Jeongwoo is unable to go back to sleep. He struggles and battles with this lack of sleep as well as his fear. Trying to backtrack, in order to pinpoint the moment when all of this started, he recalls the incident that happened when he had drinks with his childhood friend Heewon...