On the last day of a study tour to a rural hot spring town, Shunsuke rashly decided to peep at the women’s bath. However, it was a mysterious bath which had been closed to men since the olden times and he was immediately turned into a teddy bear by some strange power. He still hadn’t yet realized what had happened when his classmate Arisu entered the bath.

He was in a panic, thinking that he had been found out, but he looked just like a teddy bear. Arisu took interest in him and took him home with her. Thus began his life together with her, but being a teddy bear wasn’t his only problem. If he got an erection from sexual excitement, he would temporarily return to his human form (and naked at that)!