When Shinobu awakens one morning, he is startled to discover a blonde girl, completely unclothed, sleeping next to him with no recollection of her identity. As he grapples with the mystery of her presence in his bed, the situation escalates as his sister unexpectedly walks in on them. Now, faced with this unexpected and awkward scenario, Shinobu must navigate the ensuing chaos and uncover the truth behind the girl's inexplicable appearance.