Upon awaking one day, Anna, a high school student, realizes that she has sprouted a sudden growth of hair, inexplicable strength, and a never-ending desire for meat. Though her mother believed it to be related to puberty, things take a turn when Anna begins developing both ears and a tail, leading her to believe she is transforming into a werewolf. With the approaching full moon, Anna sets out to understand the root of her condition in hopes of preventing the transformation.