It's January of 1372 and the space-time continuum has been breached. Demons of all kind, evil and benign, spill from the netherworld into the human one.
In Paris, a series of grisly murders that couldn't be performed by a human, no matter how depraved, leads the Grand Chatelet to try and raise a demon of his own to combat whatever monster is terrorizing the city.
Unfortunately-or perhaps fortunately-the demon who is summoned brings with him...