There is a girl in their class who is always seen alone. Rarely does she talk to anyone in her class, and only her teachers could make her talk, to which she either replies "I don't know" or "I forgot". As the self-proclaimed loser of their class soon finds out, they just don't know what's truly hidden behind her. And so begins the story of our young loser - or rather, narrator as he encounters mysterious oddities day by day, and soon finds himself solving them one by one.