What's a guy to do when a militant girl demands he date her little sister? Crazy right? Well, it's exactly what happens to transfer student Kakizaki Kokera. The Harimoto Sisters have a strange love-hate relationship he just can't help but get dragged into. And what's more, there's a strange town legend about a middle schooler who cleaned up the town with overwhelming violence five years ago called Urooboe Uroboros (Half-Remembered Uroboros).