Mochizuki's high school life suddenly took an interesting turn when he reunited with his childhood friend, Tsukimi Kawaru, whom he had a crush on since they were in elementary. Through a coincidence accident, he found out that Kawaru is actually a wolf girl, who couldn't control herself around him. Because Kawaru broke her promise of keeping herself in check, her sister, Utsuru, decided to pull her back home, but Mochizuki didn't like that idea and he came up with a solution to allow Kawaru to continue attending high school while keeping her identity a secret...