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 Special Agent Jeanette LaFarge is called in to investigate a vineyard in the Reims region of France, the last thing she expects to find is multiple bodies with every vein bled dry. It’s yet another case tailor-made for Blackbird. Joining her is recent recruit Detective Daniel Murray, eager to use his newfound abilities to track down whoever is terrorizing Paris and its surrounding areas. With each ashen victim grows the realization that those responsible weren’t inspired by vampiric creatures of the night but by Elizabeth Báthory herself.

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 Lord Meriwell collapses and dies at his dining table, Barnaby and Penelope Adair are summoned, along with Inspector Basil Stokes, to discover who, how, and most importantly why someone very close to his lordship saw fit to poison him. When Lord Meriwell dies at his dining table, Nurse Veronica Haskell suspects foul play and notifies his lordship’s doctor, eminent Harley Street specialist Dr. David Sanderson. In turn, compelled by a need to protect Veronica who is at Meriwell Hall as David’s behest, David calls on his friends Barnaby and Penelope Adair for assistance.

During a vicious heat wave, a county maintenance worker stumbles upon two suspicious suitcases abandoned by the side of the road. Sheriff Bree Taggert responds to find two bodies stuffed inside the luggage. The press demands action. The community is on edge. Suddenly, Bree is at the center of a media firestorm. In Oregon, a senator’s daughter goes missing. FBI Special Agent Mercy Kilpatrick agrees to keep the politically sensitive case on the down-low.

Life is tough these days for Lydia Smith, licensed para-archaeologist. Seriously stressed-out from a nasty incident in an alien tomb, she is obliged to work in Shrimpton's House of Ancient Horrors, a very low-budget museum. She has a plan to get her career back on track, but it isn't going well. Stuff keeps happening.

On a weekend vacation, Beth Anderson is unnerved when a stroll on the beach reveals what appears to be a skull. When a stranger approaches, Beth panics and covers the evidence. But when she later returns to the beach, the skull is gone. Beth digs deeper into the mystery of the skull, and everywhere she goes, Keith Henson, the stranger from the beach, seems to appear. A body washes ashore, and Beth begins to think she needs more help than she bargained for.

Seven months ago, Pallas Llewellyn, Talia March, and Amelia Rivers were strangers, until their fateful stay at the Lucent Springs Hotel. An earthquake and a fire partially destroyed the hotel, but the women have no memory of their time there. Now close friends, the three women co-host a podcast called the Lost Night Files, where they investigate cold cases and hope to connect with others who may have had a similar experience to theirs—an experience that has somehow enhanced the psychic abilities already present in each woman.

It was one dark night that brought Damon Wolfe and Sophie Parker together. They were two tortured souls, looking for escape, and they weren't supposed to see each other ever again...Four years later, Sophie's FBI father, who is also Damon's mentor, is killed in a suspicious car crash after leaving Sophie a cryptic message to trust no one from the agency. When Damon shows up looking for her, she isn't sure if he's friend or enemy, but she knows he could easily rip apart what is left of her heart.

Detective Evan Bolton is gutted by his latest investigation. His friend and mentor, retired detective Rod McLeod, has been murdered, his body left in the trunk of a junkyard car. When McLeod’s daughter and grandson abruptly vanish, Evan knows it’s not a coincidence. Search and rescue canine specialist Rowan Wolff agrees as she and her dog, Thor, track the missing family.