"Don't." Tory rounded on Beau, her voice cracking whip-loud through the air. "I didn't ask you to do this, Beau, and I am done cleaning up your messes." She swallowed, and I got the sense that sending Beau away was even harder for her than ending things with Aaron. "Leave," she said, her voice lower. "Now."

Without waiting for a response, Tory turned back to the stage and started yelling out directions for the stagehands. "Get a doctor up here for Ms. Lawrence. Then call the head of security and inform him that we have a situation. I want this show back up and running in five minutes."

"I'm afraid that won't be possible." Agent Briggs knew how to make an entrance-in this case, with his badge held high for everyone to see. "Special Agent Briggs, FBI," he said, his voice carrying. "I'm going to need to ask you all some questions."

YOU.

Could you be any clearer? The numbers. The spiral. The dates. It's an act of contrition. An act of devotion.

An act of revenge.

You've waited so long. You've waited, and you've planned, and now that you're this close, you can feel it. The old anger, creeping back into your veins. The power.

The fear.

You will finish it. Three times three times three. You will be worthy.

This time, you will not fail.

The dream started the way it always did. I was walking through a narrow hallway. The floor was tiled. The walls were white. Fluorescent lights flickered overhead. On the ground, my shadow flickered, too.

At the end of the hallway, there was a metal door. I walked toward it. Don't. Don't open the door. Don't go in there. The warning came from my conscious mind, which knew all too well what lay down that road.

But I couldn't stop. I opened the door. I stepped into the darkness. I reached for the light switch on the wall. I felt something warm and sticky on my hands.

Blood.

I flipped the switch. Everything went white. All I could do was blink until the scene settled in front of me.

A spotlight.

A crowd.

I was onstage, wearing the royal blue dress I'd tried on in the store. My gaze traveled over the audience, picking out the ones I'd marked in advance for readings. The woman in the white vest, clutching her purse like it might sprout legs and run away. The teenager whose eyes were already tearing up. The older gentleman in the pale blue suit, sitting dead center in the front row.

This isn't right, I thought frantically. I don't want to do this. I turned, and in the wings, I saw myself. Younger. Watching. Waiting.

I woke with a start. My hands were wound tightly in the sheets. My chest heaved up and down. I was alone in the room. No Sloane. Processing that, I rolled over to look at the clock and froze.

The walls were completely covered. Sheet after sheet of paper, marked in red. This must have taken Sloane all night, I thought. She hadn't said a word when we'd gotten back to the room-not about the message from our killer, not about Aaron and the accusations Beau had flung at him.

Rolling out of bed, I went to examine Sloane's work more closely. Twelve sheets of printer paper had been affixed to the wall in four rows of three.

January, February, March...

I was looking at a handwritten calendar. Dates had been circled at seemingly random intervals. Six in January, three in February, four in March. I scanned the next row. A handful in April, only two in May.

"Nothing in June or July," I murmured out loud. My hand lifted. I pressed my fingers to the day that would always jump out at me in any calendar. June 21st. That was the day my mother had disappeared. Like the rest of the days in June, it was unmarked on Sloane's calendar.

I scanned the remainder of the months, then moved on to the rest of the walls in our room. More calendars. More dates. Taking a step back, I took in the full scope of what Sloane had done. There were years' worth of calendars on these walls, with the same dates marked on every one.

"Sloane?" I called toward the bathroom. The door was closed, but a moment later, I got a reply.

"I'm not naked!"

In Sloane-speak, that was as good as an invitation to come in. "Did you sleep at all last night?" I asked as I opened the door.

"Negative," Sloane replied. She was wrapped in a towel and staring at the mirror. Her hair was wet. On the mirror's surface she'd drawn a Fibonacci spiral. It covered her face in the reflection.

Sloane stared at herself through the spiral. "My mother was a dancer," she said suddenly. "A showgirl. She was very beautiful."

That was the first time I'd ever heard Sloane mention her mother. I knew, then, that she'd been awake all night for a reason beyond the papers on the walls.

"My biological father likes beautiful things." Sloane turned to look at me. "Tory is aesthetically appealing, don't you think? And the other girl with Aaron was very symmetrical."

You're wondering if Aaron takes after your father. You're wondering if Tory is his secret, the way your mother was his father's.

"Sloane-" I started to say, but she cut me off.

"It doesn't matter," Sloane said, in the tone of someone to whom it mattered very much. "January twelfth," she said fiercely. "That's what matters. Today's the ninth. We have three days."

"Three days?" I repeated.

Sloane nodded. "Until he kills again."

"Tertium. Tertium. Tertium." Sloane stood in the middle of our suite, gesturing to the paper-covered walls. "Three times three is nine."

I need nine.

"And three times three times three," Sloane continued, "is twenty-seven."

Tertium. Tertium. Tertium. Three times three times three.

"Remember what I said yesterday about the dates and how I think they're derived from the Fibonacci sequence?" Sloane said. "I spent all night going through the different possible methods of derivation. But this one"-she pointed to the first wall I'd investigated-"is the only version where, if you end the sequence twenty-seven dates in, you also end up with exactly three repet.i.tions within the sequence."

Three. Three times three times three.

"It was just a theory," Sloane said. "But then I hacked the FBI's server."

"You what?"

"I did a search over the past fifteen years," Sloane clarified helpfully. "For murders committed on January first."

"You hacked the FBI?" I said incredulously.

"And Interpol," Sloane replied brightly. "And you'll never guess what I found."

Security holes that the world's most elite crime-solving agencies seriously need to patch?

"Eleven years ago there was a serial killer in upstate New York." Sloane walked over to the next wall, years' worth of calendars papering it from ceiling to floor. She knelt and pressed her fingers to one of the calendar pages.

"The first victim-a prost.i.tute-turned up dead on August first of that year." She moved her hand down the page. "Second victim on August ninth, third victim on August thirteenth." She moved on to the next page. "September first, September fourteenth." She bypa.s.sed October. "November second, November twenty-third." She slowed as she brought her hand to rest on the date marked in December. "December third."

She looked up at me, and I did the mental count. Eight, I thought. That's eight.

I looked for the next date. January first.

"It's the same pattern," Sloane said. "Just with a different start date." She turned to the last wall. There was a single piece of paper on it. The first thirteen numbers of the Fibonacci sequence.

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233.

"1/1," Sloane said, "January first. In the first iteration I tried, the second date generated was 1/2. But that method limits you to dates in the first third of the month. Hardly efficient. Instead..." She drew a square around the second 1 and the 2 that followed it. "Voila. 1/12. Split in a different spot, that's 11/2, so we add both of those dates to the list. Tack on the next digit in the sequence, and you've got 11/23. Once we've made all the dates we possibly can including the first integer in the sequence, we move on to the second. That gives us 1/2 and 1/23. And if you split 1/23 after the two instead of the one, that gives us 12/3. Then on to the third integer, 2/3. February only has twenty-eight days, so 2/35 is just filler. We go on to 3/5, then 5/8, 8/1, 8/13, 1/3, 3/2, 3/21, 2/1, 2/13, 1/3-you see how January third just repeated?"

My brain raced as I tried to keep up.

"If you end the sequence after it's produced twenty-seven dates-three times three times three-you've generated exactly three repeated dates: January third, February third, and May eighth."

I tried to pa.r.s.e what Sloane was saying. If you generated a total of twenty-seven dates based on the Fibonacci sequence, you ended up with a pattern that was consistent not only with our killer's pattern, but also with a series of nine murders committed over a decade ago.

I need nine.

"The case from eleven years ago," I said, commanding Sloane's attention. "Did they ever catch the killer?"

Sloane tilted her head to the side. "I'm not sure. I was just looking at the dates. Give me a second." Sloane's eidetic memory meant that she automatically memorized anything she read. After going back over the files in her head, she answered the question. "The case is still open. The killer was never caught."

Most serial killers don't just stop, I thought, Agent Sterling's words echoing in my mind. Not unless someone stops them.

"Sloane," I said, trying to keep my mind from racing too fast. "The killer who ended his run on January first-how did he kill his victims?"

This time, it took Sloane a fraction of a second to pull the information to the front of her mind. "He slit their throats," she said. "With a knife."

I tried Sterling's cell, then Briggs's. Neither of them answered. They were probably up all night, I thought, talking to witnesses, trying to figure out who, if anyone, hypnotized Aaron's "friend" to deliver that message.

"I'm going to talk to Dean," I told Sloane. "Catch him up on what you just told me." I took in the dark circles under Sloane's eyes. "You should try getting some sleep."

Sloane frowned. "Giraffes only sleep four and a half hours a day."

Knowing a losing battle when I saw one, I let her be. Making my way quietly across the suite, I stopped outside Dean's room. The door was cracked open. I placed my hand flat on the wood.

"Dean?" I called. When he didn't respond, I knocked lightly. The door drifted inward, and I caught sight of Dean sleeping. He'd pushed his bed to one side of the room and slept with his back to the wall. His blond hair fell gently into his eyes. His face was free of tension.

He looked peaceful.

I began backing out of the doorway. The floor creaked, and Dean bolted up in bed, his eyes unseeing, his hand thrust out in front of him. His fingers were curved, like he'd caught a ghost by the neck.

"It's me," I said quickly. When he still didn't register my presence, I turned on the light. "It's me, Dean." I stepped toward the bed. It's just me.

Dean's head swiveled. He stared through me. And then a moment later, he was back. His eyes focused on mine. "Ca.s.sie." He said my name the way another person might rattle off a prayer.

"Sorry," I told him, coming closer. "For waking you up."

"Don't be sorry," Dean said, his voice rough.

I crawled onto the bed beside him. His hands found their way to the ends of my hair, his touch soft. He closed his eyes for a moment, taking in the warmth of my body. When he opened them, they were calmer, clear.

"Something's wrong," Dean said, observant as always. I wondered if he could see the tension in my shoulders. I wondered if he could feel it with his featherlight touch.

"Sloane found something." I let his touch steady me, even as it steadied him. "She derived a series of twenty-seven dates from the Fibonacci sequence. Then she did a search on the FBI's database for serial murders where one or more of the killings happened on New Year's Day."

"Briggs and Sterling gave her that kind of access?"

My facial expression must have answered that question for me.

"She hacked the FBI." Dean paused. "Of course she did. She's Sloane."

"She found a decade-old case that fits the same pattern," I told him. "Nine victims, killed on Fibonacci dates."

"MO?" Dean asked.

"Killer used a knife. He attacked from behind and slit his victims' throats. The first victim was a prost.i.tute. I don't have information on any of the others."

"Nine bodies," Dean repeated. "On dates derived from the Fibonacci sequence."

I shifted my body, leaning into his. "Last night, the message was 'I need nine.' Need, Dean, not 'want,' not 'I'm going to kill nine.' Need."

The number of victims mattered, the same way the numbers on the wrists did, the same way the dates did.

"The case Sloane found is still open," I told Dean. "It was never closed. Sterling said that serial killers don't just stop killing."

Dean heard the question I hadn't yet put into words. Could we be dealing with the same killer?

"Eleven years is a long time for a killer to deny himself," Dean said. I saw the shift in Dean before his words confirmed it. "Each time I kill, I need more. To go without, for so long..."

"Is it even possible?" I asked Dean "Can an UNSUB kill nine people and then just...wait?"

"Our UNSUB just killed four people in four days," Dean replied. "And now he's waiting. Smaller scale, same concept."

The numbers matter. The numbers told the UNSUB where to kill, when to kill, how long to wait. But making sure a portion of the sequence appeared on each victim's wrist?

From the beginning, we'd read that as a message. What if the message was I've done this before?

Suddenly, my throat tightened. Tertium, I thought.

"Dean." My lips felt numb. "What if the word on the arrow didn't just refer to Eugene Lockhart being the UNSUB's third victim this time around?"

Tertium. Tertium. Tertium. I could hear the girl saying the word. I could see her gaze staring out into the crowd.

"The third time." Dean slid to the end of the bed. He sat there for a moment in silence, and I knew he was putting himself in the killer's shoes, walking through the logic without ever saying it out loud. Finally, he stood. "We need to call Briggs."