A year ago, Yuki was paired with Moe Wakaba, a classmate of his, to purchase supplies for an upcoming school festival, preparing to give her a love letter at the right moment. In the mall, Yuno, disguised in a bunny suit, made several attempt to prevent Yuki from doing so, since she was secretly in love with Yuki, but she is stopped by the security guards. When she returned home, Yuno was revealed to have murdered her parents Saika Gasai and Ushio Gasai, a pair of bankers who were revealed to abuse her when she failed to meet their standards...