Four bodies have been discovered along Europe’s riverbanks, placed with care—and completely drained of blood. Pinpricks on their throats indicate a slender murder weapon, but DNA found in the wounds suggests something far more sinister. Tasked with investigating, the FBI recruits Agents Della Hamilton and Mason Carter to Blackbird, an international offshoot of the Krewe of Hunters. If you want to catch a vampire killer, you need agents who can speak with the dead.

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.

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.

A secret government unit is formed under the oversight of Adam Harrison, famed paranormal investigator. The case: In a historic mansion in New Orleans’ French Quarter, a senator’s wife falls to her death from a balcony. Most think she jumped, distraught over the loss of her young son. Some say she was pushed. And yet others believe she was beckoned by the ghostly spirits that inhabit the house - once the site of a serial killer’s grisly work.

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.

Aidan Flynn, a private investigator and eldest of the Flynn brothers, scoffs at the haunted-house rumors - especially since Kendall Montgomery, a tarot card reader who has been living in the mansion, is the one to tell him the tale of a woman in white. But when he finds a human bone on the grounds and another by the river, Aidan delves into the dark history of the Flynn plantation.

In the unbearable heat of another sultry Washington, D.C., summer, a serial killer is on the loose. Dr. Tess Court, one of the capital’s most successful psychiatrists, wants nothing to do with the case—until the police convince her to lend a hand to the lead investigator, legendary ladies’ man Detective Ben Paris. Scarred by his family’s history, Ben has even less use for shrinks than Tess has for him—but the forces of animal magnetism and a shared desire to catch the demented criminal known as “The Priest” inexorably erode the walls they’ve built.

At a Texas county fair, children’s book author Elle Portman is enjoying a rare night out with her favorite cowboy: her two-year-old son, Charlie. But just as they’re about to head home, the unthinkable happens: a shooter opens fire into the crowd, causing widespread panic to erupt all around them. Also caught in the melee is corporate consultant Calder Hudson. When he wakes up in the hospital, he's told he's lucky. Others didn't fare we well, which instills in Calder a furious determination to get justice.

A ritualistic murder on the side of a remote road brings in the Florida state police. Special Agent Amy Larson has never seen worse, and there are indications that this killing could be just the beginning. The crime draws the attention of the FBI in the form of Special Agent Hunter Forrest, a man with insider knowledge of how violent cults operate, and a man who might never be able to escape his own past.

When FDLE special agent Amy Larson discovers a small horse figurine amid the bloody aftermath of a gang massacre in the Everglades, she recognizes it immediately. The toy is the calling card of the apocalypse cult that Amy and her partner, FBI special agent Hunter Forrest, have been investigating, and it can only mean one thing: this wasn’t an isolated skirmish—it was the beginning of a war.