"Since that night, my brother and I have been alone in the world…" Utou Hana, the first year of high school. My life in this house is called 'the mansion of tragedy', and my brother's pact. As for me, I'm just a completely normal high school student... Or so I think. Of course, leaving aside the night walks to avenge my murdered parents and the fact that my brother craves my blood… Having your blood sucked… is it scary? Or does it… feel good? A dark fantasy work about humans and monsters, where love intertwines with mystery.