It's a pub in lower Manhattan, run by the Finnegan family for generations and now owned by Kieran and her three brothers. Kieran Finnegan, who still works there whenever she can, has become a criminal psychologist - a fitting reaction, perhaps, to her less-than-lawful past. Meanwhile, New York's Diamond District has been hit by a rash of thefts. No one's been killed - until now.

When FBI special agent Luke Kendrick discovers chilling evidence of dozens of victims at a crime scene in London, he recognizes the calling card of the notorious H. H. Holmes Society. Named for the eighteenth-century monster regarded as America’s first serial killer, the society is comprised of a twisted web of killers, working to carry out heinous murders in Holmes’s memory. And now the group’s been linked to a Scottish castle turned B and B—where guests check in but never check out.

It was stolen from a New Orleans grave - the centuries-old bust of an evil man, a demonic man. It’s an object desired by collectors - and by those with wickedness in their hearts. One day, its current owner shows up at Danni Cafferty’s antiques shop on Royal Street, the shop she inherited from her father. But before Danni can buy the statue, it disappears, the owner is found dead…and Danni discovers that she’s inherited much more than she realized. In the store is a book filled with secret writing: instructions for defeating evil entities.

Deep in the Florida Everglades, the body of a woman is discovered in pieces, presumably ravaged by an alligator. Upon closer inspection, it’s determined no animal could make such perfectly precise cuts. Only a blade could do that. Wielded by a human. Soon, dozens of oil drums emerge amid the river of grass. Each one packed to the brim with body parts.

When two hikers go missing within a series of daunting caves outside of Denver, Colorado, FDLE special agent Amy Larson and her partner, FBI special agent Hunter Forrest, have good reason to suspect foul play. The pair of hikers are only the latest to vanish after a rash of disappearances that’s left local law enforcement stumped. But in searching the dank caverns near the Arkansas River, the agents aren’t prepared for the horror they uncover: a muddy pit littered with corpses. Covered in bite marks. Made by human teeth.