Yuki Maizaino is just your average 15-year-old tomboy. That is until ALL HELL LITERALLY BREAKS LOOSE. Now; bonded and sharing a body(kind of) with a demon named Oni, a mysterious archangel named Veraventi, a surprisingly knowledgeable(on this subject at least) ally in her slightly-below-average-intelligence childhood best friend Michi, can Yuki really save everyone?