Harin, a high school girl who is bullied by delinquent classmates, is always alone.
One day, she encounters a rat that has eaten her discarded fingernails and transformed into a human version of herself.
With the help of this “rat Harin,” she takes revenge on her bullies and begins living a life completely different from before. As her life changes, her relationship with Tae-oh, the boy she has secretly liked, also starts to grow.
