Won Yoo-il leads a difficult life, all because of his unlucky name, which means "afraid of Mondays." His plight at school is further complicated by the fact that his own best friend, someone who was supposed to be a source of support and friendship, turns out to be the one ordering the bullying that Yoo-il endures every Monday. Yoo-il drops out as a result of the torment, but he bravely faces his fears and returns to a new high school, determined to start fresh and leave the pain of the past behind.