Uchiumi Tsumugi is a freshman high school who has nothing. Fail at academic and sports, shy, unable to speak up and has no friend. For a long time she enclosed herself to her own world by drawing. But for the first time in her life, in Little Monster.co,LTD (a plush doll company), she could make other people happy by her drawing. She then decided to work part-time there, unknowing there is frightening monster beyond its door...