A routine D.S.O. investigation into a mysterious cult goes horribly wrong when Leon Kennedy accidentally completes an ancient summoning ritual. Instead of unleashing some world-ending monster, he summons Y/N a demon who is now magically bound to him. With no idea how to break the ritual and a growing list of supernatural problems following them wherever they go, Leon is forced to coexist with the last thing he ever expected: a demon who may be far more complicated than she first appears.