Suzu is in charge of a special class at the school where her husband works as a substitute for a staff member who is on maternity leave. However, even though he is a temporary employee, Yuki is a problem child in the class he has been assigned to fulfill his wish. Yuki is the son of a doctor and used to be serious and get good grades, but ever since his mother left home after having an affair, he started to misbehave...