The UNSUB’s calling card had just taken on a whole new meaning. I’d assumed the numbers might have personal significance to the killer. But if they really were part of some famous mathematical sequence, there was a chance the point of the numbers was less about fulfilling our killer’s emotional needs and more about sending a message.

What message? I smoothed a hand over my dress as we began the long walk back toward the main body of the hotel and casino. That your actions aren’t emotional? That they’re as predetermined as numbers plugged into an equation?

I barely noticed the lights and sounds that bombarded our senses when we hit the casino floor.

That you’re a part of the natural order, like pinecones and seashells and bees?

Judd, Dean, and Sloane hung a left toward the lobby. Michael began veering right. “Shopping?” he asked Lia.

Somehow, I doubted that Michael and Lia, if left to their own devices in Sin City, would spend their time perusing the shops. Judd must have been thinking the same thing, because he gave the two of them a look.

“I’ll have you know I’m very fashionable,” Michael told Judd.

You saw something when security came for Sloane’s father, Michael. You asked for the check an instant later. You’re not going shopping.

Dean knew me well enough to recognize when I was profiling someone. “I’ll go with Sloane to call Sterling and Briggs,” he told me. I heard what he wasn’t saying: Go.

Whatever Michael and Lia were about to do, I wanted in on it—and if part of the reason was that going back upstairs meant going back to the information that awaited me on that drive, Dean didn’t begrudge me that.

When I was ready, he would be there.

“Fair warning.” Lia eyed Dean and me before turning back to Judd. “If you make me go up to the suite right now, there’s a very good chance that I will give a full-length performance of The Ballad of Cassie and Dean. Complete with musical numbers.”

“And there is a very good chance,” Michael added, “that I will be forced to accompany those musical numbers with a stunning display of interpretive dance.”

Judd must have decided that it was in the best interest of team harmony to avoid that performance at all cost. “One hour,” he told Michael and Lia. “Don’t leave the building. Don’t separate. Don’t approach anyone related to this case.”

“I’ll go with them,” I volunteered.

Judd eyed me for a moment. Then he gave a brisk nod. “Make sure they don’t burn the place down.”

It took exactly thirty seconds after we parted ways with the others for Michael to confirm my assumption that he hadn’t been overcome with a need to hit the shops. He came to a stop as we reached the edge of the casino floor. For several seconds, he stood there, his gaze moving methodically from one party of people to the next.

“What are you looking for?” I asked him.

“Curiosity. Irritation.” He zeroed in on a group of women coming toward us. “That mollified look people get when they’re offered free drinks in exchange for an inconvenience.” He hung a right. “This way.”

As Lia and I followed, Michael continued scanning faces. As we worked our way from the slots to the poker tables, I could sense an emotional shift in the air, even if I couldn’t pinpoint it the way Michael could.

“Incoming,” Michael murmured to Lia.

Seconds later, a bouncer was glaring down at us. “IDs, please,” the man said. “You have to be twenty-one or over to be in this area.”

“As luck would have it,” Lia told him, “it’s my twenty-first birthday.” She said those words with a coy smile and just the right level of underlying giddiness.

“And your friends?” the bouncer asked Lia.

Lia linked an arm through Michael’s. “We,” she said, “just met. And as for Miss Sweet-and-Innocent-Looking over there, I know for a fact that there are some pretty incriminating pictures of her twenty-first floating around on the interwebs, which is why my clothes will be staying on this evening.”

Did she just…My cheeks flushed scarlet as I processed the fact that, yes, Lia had really just implied that my fictional twenty-first birthday had taken a Girls Gone Wild turn.

The bouncer leaned to one side to get a better look at me. If anything, the mortified expression on my face seemed to sell Lia’s story.

“I’m going to hurt you,” I muttered in Lia’s general direction.

“You can’t hurt me,” she shot back brightly. “It’s my birthday.”

The bouncer grinned. “Happy birthday,” he told Lia.

Chalk one up for the professional liar.

“But I’m still going to need to see some ID.” The bouncer turned back to Michael. “Company policy.”

Michael shrugged. He reached into his back pocket and removed a wallet. He flashed an ID at the bouncer, who examined it carefully. It must have passed muster, because then he turned to Lia and me. “Ladies?”

Lia opened her purse and handed him not one, but two IDs. He glanced at them and raised an eyebrow at Lia.

“It’s not your birthday,” he said.

Lia executed a delicate shrug. “What’s the fun of only turning twenty-one once?”

With a snort, the bouncer handed the IDs back to her. “This area is closing,” he said. “For maintenance. If you’re looking for poker, you’ll want to hit the tables on the south side.”