Mizuno Chihiro is unable to control his urges and becomes erect very easily. Because of his constant tardiness, he was sent to participate in the re-development system together with two other problematic senpai: Takatou Shinobu and Kandori Akira. Sharing a room with Takatou, Mizuno became erect when he helped Takatou, a manga artist, with his smutty works. Takatou tried his best to help Mizuno, falling in love with Mizuno along the way. However, he refuses to admit his own feelings, hurting Mizuno in the process. What should Mizuno do?