Park Hyung Seok is an unpopular, bullied high-school student who is looked down on by his fellow student for his obesity. Bullied and harassed every day by a delinquent, he takes out his anger verbally on his mother and asks for a school transfer. Resolving to run away from his problems and start anew, he moves to Seoul and plans to attend a new high school. A few nights before he begins school, however, he receives a new body that is tall, muscular, and handsome. When one body is in use, the other falls asleep; he can switch bodies by waking up the sleeping one.