“The envelope,” Dean said as we pulled away from the runway. “Who was it from?”

Judd gritted his teeth. “He signed it ‘an old friend.’”

I froze, unable to exhale, a breath turning stale in my lungs.

“The man who killed your daughter.” Lia was the only one with balls enough to say it out loud. “Nightshade. What did he want?”

I forced myself to start breathing again.

“To warn us,” I answered without meaning to. “Threaten us. Those electrical problems with the plane. They weren’t an accident, were they?”

Judd was already on the phone with Sterling and Briggs.

Nightshade’s here in Vegas, I thought. And he doesn’t want us to leave.

I’d feared that thinking about Scarlett’s killer might conjure him up like a ghost in the mirror. I’d known that our UNSUB was attempting to attract the attention of Nightshade and the others like him. I hadn’t thought about what it would mean if the UNSUB succeeded. The organization—group—cult—

They’re here.

Five minutes later, Judd was at the airport ticket counter, attempting to book us on the next commercial flight anywhere. But the moment the woman behind the counter typed his name into the computer, her brow knit.

“I already have tickets reserved under your name,” she said. “Six of them.”

I knew before I’d even fully processed what she was saying that this was Nightshade’s doing, too. You chose Scarlett for your ninth, I thought, unable to stop myself. You chose her because she mattered to Sterling and Briggs and they dared to think they might stop you. You chose her because she was a challenge.

Of all of Nightshade’s victims, Scarlett was his greatest feat. She would be the one he went back to. The one he re-lived. You’ve watched Judd, haven’t you? Every now and again, you like to remind yourself of what you took from him—from all of them.

I wanted that guess to be off the mark. I wanted to be wrong. But the fact that Nightshade wanted us to stay in Vegas—the fact that Nightshade even knew there was an “us”…

Six tickets. The woman behind the counter printed them off and handed them to Judd. I knew before I looked that they would have our names on them.

First names. Last names.

The flight was to D.C.

You know who we are. You know where we live. The implications were chilling. Nightshade had been watching—quite possibly since he’d killed Scarlett Hawkins and Judd had moved in with Dean.

Killers don’t just stop, I thought, but in this group, they did. Nine and done. Those were the rules. Some killers take trophies, I thought. To re-live what they’ve done, to get some portion of that rush.

If Nightshade had been watching off and on, whenever he needed a fix—if he was in Vegas—then he knew what was happening here.

You’ve never killed Judd—never killed us, because the rules say you stop at nine. But an organization like yours—a cult like yours—would have a way of dealing with threats.

Lia had said it herself: if the Vegas UNSUB had been a part of this group, he would be dead. And if the cult realized that we’d made the connection, if they saw us as a threat…

Nightshade would probably love for the kids Judd was caring for to be the exception to the rules.

Judd slammed the tickets down onto the counter. He turned and was on his phone again in an instant. “I’m going to need transport, a security detail, and a safe house.”

The safe house was sixty-five miles northeast of Las Vegas. I knew this because Sloane felt compelled to share the calculation—as well as at least half a dozen others.

We were all on edge.

That night, in a strange bed with armed federal agents in the adjacent room, I stared up at the ceiling, not even trying to sleep. Briggs and Sterling were still in Vegas, working against a ticking clock to stop the UNSUB before he killed again. Another team had been assigned to take Judd’s statement about his communications with Nightshade. That statement hadn’t included any information about a cult of serial killers that had gone undetected for more than sixty years.

That information had been declared need-to-know.

Outside of our team, only two people had been read in—Agent Sterling’s father, FBI Director Sterling, and the director of National Intelligence.

Two days, I thought as the clock ticked past midnight. Two days until our UNSUB killed again—unless Nightshade killed him first.

You’re here to clean up a mess. I could feel my heart pounding in my throat, but I forced myself to go deeper into Nightshade’s psyche. Your work is neat. Clean. Poison is an efficient enough means of removing pests.

I tried not to wonder if Nightshade was the only one whose attention our UNSUB had caught.

I tried not to wonder if the other members of the cult knew about us, too.

You could have killed this UNSUB, I thought, focusing on Nightshade, the evil I could name. As soon as you got here, you could have killed this imposter making a mockery of something he does not understand. Throwing it in your faces. Attempting to fashion himself into something more.

So why wait? Had Nightshade not made any more progress than we had at identifying the UNSUB? Or was he biding his time?

That was the question that dogged me the first night in the safe house. The second night, my thoughts shifted toward the way Nightshade had signed his message to Judd.

An old friend.

It feels true to you, doesn’t it? I thought. That killing Scarlett linked you and Judd. You chose her for what she was—a challenge, a slap in the face to Sterling and Briggs. But after…