It's January of 1372 and the space-time continuum has been breached by a great rift. Demons, imps, and spirits, evil and benign, spill into the universe from the netherworld. In Paris, a series of grisly murders that couldn't possibly be performed by a human, no matter how depraved, leads the Grand Chatelet and his men to try and raise a demon of their own to learn how to combat the creature that is terrorizing the city. Unfortunately-or perhaps fortunately-the demon who is summoned brings with him a van from the Paris of the twenty-first century. The van contains a modern day drama teacher, her son, and eight precocious high school students-along with all of their electronic devices. Soon, their laptops, tablets and cell-phones become possessed by imps and spirits of the netherworld, some of whom are brilliant and all of whom are insatiably curious. Soon it's a race to see which pack of outsiders can create the most turmoil in the late Middle Ages-monstrous demons or precocious teenagers who soon have their own allies and followers among the ranks of demonkind. And King Charles V had already been in trouble! Piled onto his own poor health, a suspicious and contentious church, France's always-quarrelsome nobility-worst of all, his unscrupulous and ambitious brother, Philip the Bold-the king now has both demons and people from the future to contend with. He does have one asset-and not a small one. He can place his trusted Constable of France, Bertrand du Guesclin, in charge of the rambunctious teenagers from the future and their ever-growing legion of demons. And Bertrand has a great asset of his own-his wife Tiphaine de Raguenel, perhaps the best astrologer in all of France and, for sure and certain, not a woman to take seriously the prattling nonsense of youngsters skeptical of her lore and knowledge.