Kakeru Kibaf's homeroom teacher, Wakasa, is young, handsome, and well-known as the always smiling... that is, until an accident leads Kakeru to discover that "Mr. Nice Guy" is actually "Mr. Foul-Tempered, Sexually-Harrassing Pervert " But, what will happen when he suddenly finds himself living with said Mr. Pervert at the start of the new school term?