ECKER AND LANCASTER had sealed off Debbie’s bedroom and called in the forensics team, which had gone over the room and the house in meticulous detail. Burlington had never suffered a crime such as this one, and everyone, from the rookie on the team to the most senior departmental official, was bringing his A-game.

The Watsons said they knew nothing of the musical score. Decker tended to believe them. After the forensics team finished, Decker and Lancaster sat down with the Watsons once more.

“If the guy came to this house to write the score on the wall, could he do so without your knowledge?” Decker asked them.

“Well, we do have to sleep,” said a defensive Beth. “But the house isn’t that big. And our room is right next to Debbie’s. George and I are both light sleepers. I don’t see how she could have had a guy in her room and we not know about it.”

“What about during the day?” said Lancaster.

“I’m a stay-at-home mom. George is a nine-to-fiver. I’m here a lot more than Debbie, actually.”

“How long ago do you remember seeing the musical score on the chalkboard?” asked Decker.

“It wasn’t there two weeks ago, I can tell you that,” she replied.

“How do you know that?” asked Decker.

“Because I wiped the whole thing clean.” She paused. “We’d had an argument and I just, well, I lost it and wiped all that crap off.” She let out a little sob. “And now I’ll never see her again.”

“Argument about what?” asked Decker, ignoring her distress. He needed answers. And he needed them now. She could grieve later.

Beth composed herself. “Debbie was a senior. She took the SAT and did okay, but she hadn’t applied to one damn college. She made excuses about cost. And it’s true that we can’t really help her out. But I kept telling her there’s financial aid out there. And without a degree what was she going to do? Be me?” She paused again as her husband looked away. “So I lost it and wiped her damn board clean. All those messages she had on there about changing the world and having a purpose. It was bullshit! She was doing nothing and going nowhere. So I wiped it clean. Clean slate. Hoped she’d get the point. Guess she didn’t. Guess she never will now. Not now. Oh, shit, my baby. My baby.”

Beth dissolved into tears and started writhing uncontrollably on the couch. With Decker’s help her husband managed to get her into the bedroom to lie down. Decker could hear her calling out to her dead daughter the whole way as he walked back down the hall to join Lancaster.

George Watson came back out a few minutes later and said, “I think we’re done for now, if that’s all right.”

Decker said, “Have you and your wife gone away on a trip recently?”

George looked at him in some amazement. “How did you know that?”

“The guy came here and wrote what he wrote. If you had been here you probably would have seen him. And he wouldn’t take that kind of chance. So you were gone at some point?”

“A week ago we drove to Indiana to be with Beth’s sister. She was ill. We were there two days and then drove back.”

“And Debbie stayed here?”

“Yes, we couldn’t take her out of school.”

“So that’s probably when he came,” said Decker.

George began to shake, wrapping his arms around himself. “Do you really think that animal was in our house? In our daughter’s bedroom?”

Decker gave the man with the wrecked arm the once-over. “I think it’s highly possible, yes.”

Lancaster gave Decker a fierce stare and said quickly, “Well, thanks for your help, Mr. Watson. We’ll be going now. And we’re very sorry for your loss.”

George walked them to the door. As he opened it he said, “Debbie wouldn’t have helped anyone kill people at Mansfield. They were her friends.”

“I can appreciate that,” said Decker. “I hope it turns out you’re right.”

George blinked rapidly, as though he had never considered that he might be wrong. He shut the door behind them.

Decker and Lancaster walked down the sidewalk.

“Your bedside manner is as terrific as always,” said Lancaster sarcastically.

“I’m not here to be his friend and hold his hand, Mary. I’m here to catch whoever killed his daughter.”

“Okay, okay,” she said, “I got an email from forensics. They found nothing pertinent on Debbie’s phone or laptop. No photos, emails, texts, voicemails. And there are no online postings on any site they could think of or whichDebbie had access to. Her mom said she had seen some alluding to this guy, but Debbie must’ve deleted them. But maybe our guys can still dig them up somehow.”

“This guy would never have let her take his picture. No electronic trails either. Far too easy. Our guy may not even have Web access.”

“How do you figure?”

“I’m seeing someone outside the mainstream. No ties. A loner. He floats from place to place.”

“Based on what? Something you saw?”

“No, something I felt. But one thing has me puzzled.”

“Just one, you’re lucky then,” she said, smiling grimly. “My list is six pages long.”

He went on as though he hadn’t heard her. “Why Debbie? Why pick her to team with?”

“Team with? What exactly did she do? I thought she was just his girlfriend.”

“She gave him something he needed.”

“Something he needed? At the school? You don’t mean the guns? There’s no way she’s lugging in a pistol and a shotgun.”

“I don’t necessarily mean the guns, no.”

“But why would he need her to bring him anything?”

“That’s what’s puzzling me too. Why her and why the meeting at the school on that day?”

“Whoa, Decker, you’re pulling way ahead of me. What meeting?”

“She pretended to be sick. She got out of class, met this guy, probably gave him something, and then he killed her. But there’s a time gap that I can’t figure right now.”

She asked him another question, only Decker wasn’t listening. His gaze was moving down the street, to his left. It was dark, the night air chilly with mist rising from both their mouths as they exhaled. There seemed to be nothing good out in that blackness. But to Decker the night was suddenly full of threes, his least favorite number.

It had first happened when he was a rookie cop. Thankfully he’d been out on patrol alone. He’d been sitting in his squad car sipping coffee when out of the darkness came movement. At first he thought it was some people trying to sneak up on him. Back then Burlington had a big gang problem, mostly consisting of young men with no jobs and no hope, too much testosterone, and access to too many guns.

He’d thrown his coffee out the window, his hand had gone to his gun, and his other hand to his radio. He’d been about to step out of the vehicle and give a warning to whoever was out there. That’s when the figures appeared clearly in front of him. Giant, towering number threes.

It was like he’d been suddenly propelled into a bad sci-fi novel.

He thought he was going mad. But something coalesced in the middle of his brain. A small scrap of memory from one of the doctors at the institute outside Chicago where he’d gone after his injury and all the weird things had started happening to him.

The doctor had said, “Amos, for you, a new day can mean new things. The brain never stops. It is relentless. It is constantly configuring and reconfiguring. I’m trying to tell you that what has happened to you so far may not be the only change you experience with your mind. Tomorrow, next month, next year, a decade hence, you may wake up and discover it is doing something else. There is no way for us to predict it, unfortunately. And it may be terrifying when it does happen. But just know that it’s your mind. It’s just all in your head. It’s not real.”

With that remembrance, Decker turned back to face the army of numbers, his initial fear receding, but it was replaced with a fresh one.

What new stuff will tomorrow bring?

He had gotten off duty, gone home, dropped into bed, and wept quietly so that he wouldn’t awaken Cassie. In the morning he told her what had happened. She was predictably supportive and encouraging. And Decker was predictably upbeat, blowing it off as something that was actually funny. But it wasn’t funny. It wasn’t funny at all. The threes had been gone for a while. In fact, he hadn’t seen them coming out of the darkness since Cassie and Molly died. But now they were back.

Wonderful.

And the threes had added a new dimension. A trio of knives was coming off each of the digits’ stems. No, not funny at all.

“Let me know if they crack the code,” he said as the threes charged forward, knives at the ready.

Then he turned left and headed down the street.

“Don’t you want a ride home?” asked Lancaster.

Decker kept walking, his hands shoved deeply into his coat pockets.

He didn’t need a ride. He needed to think.

He looked at his feet to avoid staring into the faces of the legions of numbers coming at him from out of the gloom.

What did Debbie Watson have that their shooter needed? Guns? No. Cammie gear? Maybe. But why couldn’t he have brought that on his own? He didn’t need her for that.

The heart and the picture. She was in love. She had a crush on the guy. Would do anything for him. But would she sacrifice her classmates? The picture of the cammie man had not included any weapons. Had Debbie not known what the actual plan was to be? So why had she come out of her classroom to meet the guy?

He lifted his eyes, saw the threes flying head-on at him, and lowered his gaze once more. When he had done stakeouts or pulled shifts at night he had worn special glasses that tinted the darkness into a golden color. Gold for him was a sky full of geese. No threes to bother him. He had lost the glasses a long time ago. Now the threes were back and they were armed. He would need to get new glasses.

He stopped walking, leaned against a tree, closed his eyes, dialed up his mental DVR, and replayed everything he had seen in the Watsons’ house. The spool unwound in his head and then he slowed the pace of the mental frames. And then he stopped his DVR and a row of images stared at him like figurines on a fireplace mantel. Actually, the image was quite literal.

They were on the fireplace mantel.

Decker turned around and walked quickly back to the Watsons’ house. He knocked and George answered.

“Did you forget something?” George asked, sounding a little annoyed.

“Pictures on your mantel. I saw them earlier. Can you walk me through them?”

“Pictures on the mantel?” said George with a perplexed look. “Walk you through them?”

Decker stepped inside the house, forcing the much smaller man to step back quickly.

“I’m assuming they’re family members?”

“Yes. But what does that have to do with anything?”

“I’ve worked cases long enough to know that it’s the one thing you let pass that ends up holding the answer you need. We can’t afford any lapses here, Mr. Watson, I’m sure you can understand that. If we’re going to find whoever killed Debbie and the others.”

What can the man say to that other than agree?

Watson slowly nodded, though he still looked unconvinced. “Okay, sure, follow me.”

He led Decker into the small living room and over to the mantel that topped an old brick fireplace that had mortar leaching from the seams.

“Where do you want to start?”

Decker pointed to the picture on the far left. “With him.”

“Okay, that was my wife’s father, Ted Knolls. He died about two years ago. Heart attack.”

“What did he do for a living?”

“What the hell does that have to—”

Decker cut him off. “Just tell me what he did for a living.”

Decker looked menacingly down at the smaller man. He was a grizzly against a chipmunk, which was exactly how he wanted Watson to see it.

Watson took a step back, changed color, and looked at the photo. “He was a long-haul trucker. Bad diet, no exercise. He was as big as a house when he collapsed on his front lawn picking up the newspaper. He was dead before he hit the grass.” He eyed Decker’s massive frame when he said this. “But that’s all he did, he drove a truck back and forth across the Midwest and down to Texas and back.”

“Was he close to Debbie?”

Watson self-consciously rubbed at his malformed arm. “No, not really. I mean, we saw them at holidays. But, to tell the truth, things weren’t good between us and them. My mother-in-law never warmed to me.”

“And the man next to him? That picture looks pretty old.”

“That’s my grandfather, Simon Watson. He’s been gone, oh, a good six years. He was a young man in that picture.”

“So Debbie’s great-grandfather,” said Decker, and Watson nodded.

“He lived to over ninety years old. Smoked and drank and didn’t give a damn, as he liked to say.”

“But Debbie knew him if he’s only been gone six years?”

“Oh, yes. In fact he lived with us the last five years of his life.”

“So she would have spent time with him?”

“I’m sure she did. Debbie was still a kid then and Gramps had had a pretty interesting life. Fought in World War II and then the Korean War. Then he left the service and went to work for the civilian side of the Defense Department.”

“Doing what?”

“Well, he worked at the military base here when it was open.”

“The one next to Mansfield High School? McDonald Army Base?”

“That’s right.”

“What did he do there?”

“He had a series of jobs. His training was in engineering and construction. So he worked on the facilities and plant side.”

“Do you know the dates?”

“Come on, what does this have to do with anything?”

“I’m just looking for leads, Mr. Watson. The dates?”

“I can’t tell you for certain.” He paused and thought about it. “He left the regular Army in the sixties. Then he went to McDonald probably around 1968 or ’69. It must have been ’69. I remember associating it with the astronauts walking on the moon. Then he worked there until he retired. About twenty years later.”

“And the base closed eight years ago.”

“That sounds about right.”

“That wasn’t a question, Mr. Watson, it did close eight years ago, on a Monday. There was sleet that day.”

Watson looked at him strangely and then coughed. “If you say so. I can’t remember what I was doing last week.Anyway, it was part of a Pentagon base realignment and Burlington lost out. I heard tell most of the operations moved east, maybe to Virginia. Closer to Uncle Sam and his dollars in D.C.”

“So, presumably Simon talked about his work at the base with you, with Debbie?”

“Oh, yes, I mean the parts he could talk about. Some of it was classified, I guess you’d call it.”

“Classified?”

George’s features eased to a grin. “Well, I don’t think they did nukes or anything there. But the military always has its share of secrets.”

“So what did Simon talk to you about? I mean with the base?”

“Some of the history of it. People he met. Some of the work he did. They kept adding on to the base for years. Building, building, building. All the people who worked there sent their kids to Mansfield for high school. His son—my father—went there. So did I. So did my wife for that matter.”

“Did Debbie ever mention to you some of the things she and her great-grandfather talked about?”

“Nothing that I really recall. As Debbie got older she didn’t spend as much time with him. Old people, young kids, oil and water. Gramps wasn’t as much fun, I guess.” He looked down. “And I guess neither was I.”

“Okay, take me through the other pictures.”

A half hour later Decker was on his way through the dark streets once more.

Cammie man had gone to the Watsons’ house and written on that wall in code disguised as a musical score. That he was sure of. He didn’t know what the message said, and he didn’t know what the man had needed fromDebbie. Yet out of all the students at Mansfield, why ally himself with her? There must be a reason. A good one.

His phone buzzed. It was Lancaster.

“The Bureau thinks they broke the code. It was some sort of substitution cipher. Pretty simple actually. Well, actually, they’re certain they did crack it.”

“How can they be certain they did?”

“Because of what the message said.”

“Don’t keep me in suspense, Mary. What did it say?”

He heard her release a long breath that seemed filled with apprehension.

“It said, ‘Good job, Amos. But in the end it won’t get you where you want to go, bro.’”