“Multiple killers.” Dean hadn’t looked at the spread for more than thirty seconds when he said the words. “And it’s not just a shift over time. Even back-to-back cases have totally different signatures.”

To some of you, choosing the victims is paramount. To others, the target is beside the point.

Eleven cases. Eleven different killers. Nightshade didn’t kill those people in New York. Viewed in the context of the larger pattern, it was easier to see. Nine victims, killed on Fibonacci dates. Everything else—everything that told us who the killer was—was different. It was like looking at eleven people writing the same sentence, over and over again. Different handwriting, same words.

So where did that leave our Vegas killer?

“Seven different methods of murder.” Sloane’s voice broke into my thoughts. Like her, I counted. One set of victims had been strangled. The New York killer had slit his victims’ throats; another had also used a knife but showed a preference for stabbing. Two sets of victims had been impaled through the heart—one with metal bolts and another with whatever happened to be on hand at the scene. Two sets had been beaten to death. A case in Paris featured victims who were burned alive.

The most recent case—only two and a half years old—was the work of an UNSUB who broke into homes and drowned the inhabitants in their own bathtubs.

And then there were the ones who’d been poisoned.

Sloane stood, staring down at the pictures. “The closest cases are three years apart.” Sloane squatted and began pulling out photos—one from each case for which we had them. With the same efficiency with which she’d organized the glass objects on the shelf in our room, she began ordering them, spacing some closer together than others. She waved for paper, and Michael supplied it.

What does Michael see when he looks at these pictures? The thought struck me suddenly and violently. Is there any emotion on a dead person’s face?

Beside me, Sloane scribbled on sheets of paper, making notes about the cases we didn’t have pictures for. She integrated those in with the others on the floor.

There’s a pattern. I didn’t need her to tell me that. To these killers—however many of them there were, whatever they were doing—the pattern was everything.

Sloane kept tearing pages off the notepad. The sound of her ripping sheet after sheet off was the only one in the room. She placed the blank pages in open gaps.

“Assume a three-year interval between each case and the one that follows,” Sloane murmured, “and you can extrapolate where we’re missing data.”

Three years, I thought. Three is the number.

“It repeats.” Sloane jerked back, like she was afraid the papers might infect her, like she was afraid they already had. “Every twenty-one years, the pattern repeats. Impaled, strangled, knifed, beaten, poisoned, drowned, burned alive.” She made her way down the row, filling in methods for the blank pages. When she started over, her voice went up an octave. “Impaled, strangled, knifed, beaten, poisoned, drowned, burned alive. Impaled—”

Her voice broke. Michael caught her and held her still, his arms wrapping around her and pulling her back to his chest. “I’ve got you,” he said.

He didn’t tell her it was okay. We all knew it wasn’t.

Dean crouched over the pattern Sloane had pulled out. “Cassie,” he said.

I knelt. Dean tapped one of the photos. Drowning. Starting there, I realized why Dean had called me over and not Sloane. Drowning, burning alive, impaled through the heart—

Alexandra Ruiz.

Sylvester Wilde.

Eugene Lockhart.

Our UNSUB was going in order.

You need nine, because that’s the way this is done. Those are the rules. My understanding of the Vegas UNSUB shifted. There is an order. You’re following it.

But being a follower isn’t enough.

The numbers on the wrists, the Fibonacci spiral—none of that was present in any of the other cases Sloane had pulled. Each of the cases in front of us had employed one of seven methods.

You’re going to do it all.

“Where are we in the cycle?” I asked. “Is our current UNSUB part of it, or does he break it?”

“Last case was two and a half years ago,” Sloane said. “Three years before that, we have the Nightshade case.”

Six years in May, I thought.

“So the UNSUB is early,” I said. “Unless you go based on calendar year, and then—technically—it fits the pattern.”

Alexandra Ruiz had died after midnight on New Year’s Eve. January first. A date for beginnings. A date for resolutions.

“If we assume the UNSUB started at the beginning of the established cycle,” Dean said, “then that cycle starts with drowning.”

The most recent set of nine victims had been drowned.

“This isn’t a culmination,” I translated. “It’s not a grand finale. If it were, it would have happened before they started the cycle over.”

They. The word settled over me and refused to leave. “Who’s doing this?” I asked, looking down at the pictures. “Why?”

Hundreds of victims killed over decades. Different killers. Different methods.

“They’re doing it because someone told them to.” Lia managed to sound utterly bored, but she couldn’t look away from the pictures splayed out on the floor. “They’re doing it because they believe this is how it has to be done.”