Prologue

The dirt was the first giveaway. Nothing might have been obvious to the casual observer walking by the ruins of Remington House, but when he’d been called out to join Detective Chief Inspector Mark Billingham, Luke Kendrick already suspected that the killer he’d been tracking had taken up residence in the United Kingdom.

And the dirt was the first giveaway.

It was filled with bone fragments.

Luke knelt, gingerly sifting through the pebbled dirt. At first, he found nothing but tiny fragments that he collected in an evidence bag. Then he found a larger piece and studied it carefully. A forensic crew needed to be called in, but he had something to go on. He’d found a finger bone, a phalanx, that suggested someone with long hands, perhaps a musician...

And perhaps that meant nothing. Maybe it was just his imagination, him personifying something he hadn’t begun to define other than that...

It was human.

And he couldn’t help but picture the situation that had brought him here, the old manor back in the States where police had discovered so many incomplete skeletons, so much blood and acid, so many furnaces...

All evidence that pointed to the man known as America’s first serial killer, H. H. Holmes, the alias of the infamous Herman Mudgett, and his “Murder Castle,” where dozens had come to attend the Chicago World’s Fair in 1893.

He realized Mark Billingham was looking at him.

The Englishman was a solid officer—a man so concerned with the reports of screams having come from the area along with a rash of missing persons that he wasn’t the least offended by the fact an FBI agent from the US might be a person who could help him. Nearing sixty, Billingham still stood as tall and straight as a ramrod and he’d managed to keep an incredible head of thick, silver-white hair.

Luke rose and offered the evidence bag to Billingham. “Human remains, beyond a doubt. While I don’t have a medical degree, I’ve been around long enough—”

“Indeed,” Billingham said dryly. “I, too, am able to recognize a human finger.”

Luke grimaced and nodded. “Right. Of course. We need to rip the place apart. I’m going to suggest you get Forensics out here as quickly as possible, though I believe whoever was perpetrating the crimes here has moved on.”

“I’ll put in the call but, while we wait, I’d like to explore the rest of the place,” Billingham said.

“Of course.”

They had only come as far as the entry. Once, Remington House had been the crowning jewel in a massive noble estate. But after being bombed in World War II, it had passed from owner to owner, all hoping to restore its grandeur, all discovering the fantastic sum needed to do so. It had recently been taken over by a historical society, one still in the process of acquiring the necessary paperwork and funds to restore the manor structure itself. Once, however, the grand entry had led to a massive ballroom and stairs to an open balcony overhead, which led into bedrooms and guest rooms, while the dining hall and servants’ quarters had led to the left.

“I’ll head up and you’ll take this floor?” Billingham asked.

“Sure. No, wait. I believe there was a basement. I’m heading down,” Luke told him.

“That was where...” Billingham began. He shook his head. “I read the reports. The man who carried out the horror in the US was—”

“Killed,” Luke said flatly. “Yes, he was shot when he tried to use one of our forensic people as a shield, threatening to slit her throat.”

Luke knew that for a fact. He’d been working undercover and had been with the team who had discovered the small inn aiding the H. H. Holmes Society. And while he hadn’t been the one to shoot the man, he had been the one to give the order to take the shot. They all knew that it was regrettable. They didn’t take human lives unless they had to. Nathan Briar, the killer they’d trailed and cornered, had died without giving them information they desperately needed.

But since his blade had rested against the throat of Debbie Lyons and tiny rivulets of blood were already seeping down her neck, there had been no choice. But the two-hundred-year-old manor where Nathan Briar had been practicing his depravities had been purchased by a shell corporation in the Cayman Islands and that just kept leading the best techs in the world down a rabbit hole. But in that old edifice, they’d found acid vats, a giant furnace, all kinds of chemicals and of course...

Bits and pieces of human remains.

And then one more thing. A scrap of paper that hadn’t quite made it into the fire with a happy face and a short message.

“The H. H. Holmes Society.”

“Basement, of course,” Billingham said. “I’ll go with you, if I may.”

“Of course,” Luke assured him. “The entrance to the basement is usually around a kitchen or a food staging area in older places, so we’ll head there first.”

They did.

They followed old stone steps down below the earth, the wooden handrails long ago rotted and fallen apart.

But in the dark dampness below the main structure, Luke immediately saw what he had feared. A massive furnace recently used. Wooden tables, stained with blood. And as Billingham switched on his heavy-duty flashlight, they immediately saw that, placed in a far corner of the room, someone had been left to greet them.

A skeleton.

Set on a stand, with its wired hand and finger bones lifted to the forehead in a salute.

Luke shook his head, inhaling a deep breath. He looked at Billingham and said quietly, “Detective Chief Inspector, I’m truly sorry to say I believe the H. H. Holmes Society has now traveled to your jurisdiction.”

“Did you kill the wrong man?” Billingham asked, frowning.

“No, sir. You’re missing the point. The H. H. Holmes Society.We have been desperately searching through the dark web. Someone out there is creating a...league of killers, all hoping to imitate and outdo the man known as America’s first serial killer. Some even suspect he might have come to London before he created his Murder Castle in the US. And he might have begun his killing career as Jack the Ripper. But for the present—”

“There’s a society of such killers?” Billingham said with horror. “But how—”

“As of now, we’re working on little but theory,” Luke explained. “And a scrap of supposedly burned paper our forensic team was able to salvage. Also...body parts. But there are differences now—forensic detection is light-years better, we have fingerprinting, DNA—”

“Enough to catch a killer,” Billingham said. “But an unknown numberof killers?”

Luke stared at him solemnly. “Along with our scientific methods being better these days, so is underground communication online. Out in the open, botanists find other botanists, new moms find other new moms, and killers also find like-minded friends.”

“Then we can shut them down—find the head of the snake and hack it to pieces!” Billingham said passionately. “Between our international tech departments—”

“I believe we have some of the best people in the world,” Luke assured him. He hesitated.

Murder was as old as humanity. Murder could occur over love, jealousy, greed and a dozen other factors. Those murders could usually be solved.

But this situation...

Herman Mudgett, aka H. H. Holmes, had not been a man who looked like a crazed killer; rather, he’d been highly educated, receiving his doctorate from the University of Michigan, one of the most prestigious schools of his day. He’d been a ladies’ man, charming, intelligent, so much so that he had been very successful at convincing and seducing people, many to their deaths. He went through much of his life appearing to be an upstanding and well-admired businessman.

He liked money; many of his murders had to do with insurance fraud, and in the end, he was arrested first for his financial crimes. Insurance fraud was one of his favorite schemes to get money—of course, this often meant murdering someone to get his hands on that money. And it was after his arrest that the true purpose of his Murder Castle had been discovered. He’d confessed after he’d been convicted of many of his murders, but even in his confession he attempted to deceive, confessing to murdering some who had still been living at the time.

He had written in his last missive to the world that he had felt no more about destroying the bodies of those he’d killed with acid or fire than he might have felt burning any inanimate object.

He’d talked about being Satan or the son of Satan. Maybe, as a true psychopath, he wasn’t that far off.

Luke realized that Billingham was looking at him, waiting for him to speak. Before he could respond, the detective chief inspector took the initiative.

“In other words, I’m not just looking for a serial killer—I’m looking for several? At least until we find whoever has that dark-web site going?”

Luke nodded grimly. As he did so, his phone rang. He excused himself to Billingham to answer the call.

It was Mason Carter, recently promoted to field director for their Special Circumstances Unit, European Division.

For a time, he and Della Hamilton had been the only special agents in the European Division. And then...

This.

Mason and Della were in France, following a request from Interpol. But Luke knew something was wrong the minute he heard Mason’s voice.

“You need to get just north of Edinburgh. As quickly as possible. Special Agent Carly MacDonald is checking into Graystone Castle, and we’ve been contacted by Interpol—several people heading to the Highland Games being held in the area have disappeared. Of course, everyone knows what happened in the United States—”

“Right. That’s why I’m where I am now,” Luke reminded him.

“I know, but I think we’re looking at an active site. People who had mentioned to others they might check out Graystone Castle are among those who can’t be reached. I know you’re already working at a site, but...I think this is going to take precedence. We gave her the go-ahead—she knows what we’re up against, but everyone needs backup. Can you get up there quickly? She went in as a tourist.”

“She’s not among the missing already, is she?” Luke asked. “I haven’t worked with her—”

“No, no, but from her report, nothing we’ve come across so far resembles the Murder Castle so completely. It is a centuries-old building and it’s been refurbished in an interesting way. I believe she’s going to need backup as quickly as possible.”

Luke looked at Billingham.

“I’m on this. We’ve got bodies, but the killer is gone. Trust me—we’re good,” the man told him.

Luke nodded. He knew Billingham and his people were among the best.

“Luke?” Mason said over the phone line.

“I’m here.”

“Well, get there, quickly, please. Graystone Castle is now a bed-and-breakfast. But from what we’re hearing...”

“What?” Luke asked.

“It’s just like ‘Hotel California,’” Mason said dryly. “From what we’ve learned so far, people check in—and they don’t check out.”