A magical world populated by supernatural creatures exists alongside ours. Once in a while a portal between the two opens. Demons known as BEMs ("big-eyed monsters") have stolen precious jewels and escaped to Earth through that portal. It is up to two demon hunters, Lime and Bass, to assume the likeness of a teenage girl and boy and restore peace and order.

A magical world populated by supernatural creatures exists alongside ours. Once in a while a portal between the two opens. Demons known as BEMs ("big-eyed monsters") have stolen precious jewels and escaped to Earth through that portal. It is up to two demon hunters, Lime and Bass, to assume the likeness of a teenage girl and boy and restore peace and order.