Yuya Nomoto, an ordinary college student, met a mysterious high-school student called Hitomi. At a deserted landfill, he saw her transform into a beast and fight a Leo monster. They''re Brutes who have brains of humans and fangs of beasts. Hitomi is a Ratel, a Brute with the strongest killer instinct. Nomoto gets involved in their battles called Killing Bites.