"What does that have to do with anything?"

"Locard said that a criminal always leaves something at the crime scene and always takes something away." She remembered Harriman telling them that an ambulance had taken Lucy to the hospital.

"But I wasn't there. And I'm not a criminal."

Was Nick being deliberately dense? Ruby stamped her foot. "But isn't that true for whoever is at the scene? True for, say, the paramedics? What did they leave behind? And where did it come from? Remember how you got sick that night we helped Mariana?"

Nick grimaced. "How could I forget?"

"So some of that vomit must have gotten on her. Remember how you wiped your mouth afterward? And then you held her hand when the paramedics were working on her? Until they needed to clip on the pulse ox? They change gloves between patients, but they don't change everything. I'll bet you anything that the EMTs who took Lucy Hayes to the hospital were the same ones who helped Mariana earlier. Some of your vomit must have gotten on the pulse ox and later been transferred to Lucy."

Nick's face went slack as the implications sank in.

Just in case, Ruby spelled it out for him. "You aren't the common denominator. The paramedics are. They accidentally carried your DNA from Mariana to Lucy."

Her phone rang. Ruby was going to ignore it, but then she saw it was Alexis. Maybe she would figure it out faster than Nick had. He still looked like it was sinking in.

"h.e.l.lo?" Ruby said.

No answer.

"h.e.l.lo?" Ruby tried again. "Alexis?"

Nick shrugged. "She must have b.u.t.t dialed you. Just hang up. We need to tell Harriman."

But Ruby heard someone talking in the background. It sounded like Alexis. She stuck her index finger in her other ear and closed her eyes.

"What do you want?" she heard Alexis say. "Why do you have a gun?"

And then Ruby realized there was a missing part to her equation. If Nick hadn't killed Lucy, who had? She had the sinking feeling that the answer to that question might be the person Alexis was now talking to.

A new voice spoke. "Don't worry about that now. Just start driving and follow my directions." The voice wasn't as clear as Alexis's, but it was definitely a man's.

Ruby turned, opened her eyes, and started frantically drawing on top of the counter with her index finger. The salesman looked at her like she was crazy, but Nick got it.

"Do you need a pen?"

She nodded. While Nick wrangled one, she heard more exchanges between Alexis and the man that made the hair rise on the back of her neck. When the clerk pushed the paper and pen toward her, she scribbled, "Alexis kidnapped. Can hear her talking to guy."

When Alexis started asking about turning onto Seventeenth from Powell, Ruby knew right where Alexis was. Where she and the person who was holding the gun on her were. Close to the Ross Island Bridge.

Alexis was in trouble. Did she even know whom she had dialed? Was she just hoping that whoever it was would listen, wouldn't hang up?

They needed to call the police and let them know what was happening. They couldn't use Ruby's phone without first hanging up on Alexis. And if they used Nick's phone, the cops would show up first and ask questions later. That left the new phone.

"Take notes," she wrote for Nick, and underlined it. Then she handed him the phone, pushed over the paper and pen, and tore open the package holding the new phone.

Of course, this phone didn't have Harriman's direct number, so she had to call 4-1-1. She was transferred to Central Precinct. When she asked to be transferred to Harriman, it wasn't even him who answered.

"Detective Meeker."

"I need to speak to Detective Harriman. It's urgent."

"He's busy right now. But he's my partner. What do you need?"

"Okay." The words crowded into Ruby's mouth. "Alexis Frost has been kidnapped."

"What?"

"I just got a call from Alexis. Well, maybe not from her, because she's not speaking directly to me. But I can hear her in the background talking to some guy. And she's saying things such as 'Don't shoot me.' I'm pretty sure she's with the real killer. And she was saying she was driving down Powell. Toward the Ross Island Bridge. You have to stop him before he kills her."

"Let me ask you something. Have you been drinking?"

"What?" Ruby felt her face get hot. Urgency tangled her words. "No! This is Ruby McClure. Detective Harriman knows me. And he knows Alexis. See, Nick's DNA got on Lucy Hayes's hand because of the paramedics. And now the guy who really killed her has taken Alexis."

"So you're a friend of Nick's?"

"Yes," Ruby said with relief.

"Look, I appreciate you trying to throw a red herring into the mix to help a friend, but I don't have time for this. I'm hanging up now."

And then Ruby was left with nothing but dead air.

CHAPTER 48.

ALEXIS.

MONDAY.

NOT PERSONAL.

"What?" Alexis's heart stuttered. "Why do you have to kill me?" She didn't realize she had lifted her foot from the accelerator until he nudged her again with the gun.

"I'm sorry. It's not personal." He said this as if she would find it rea.s.suring. "It's just that I made a mistake and now I have to fix it."

Her hands were slick on the wheel. "And how does killing me fix a mistake? Isn't that just another type of mistake? Like two wrongs don't make a right?"

Instead of answering, he said, "Turn here."

"On Pierson?" she asked. It was a silly exercise. No one was listening. Alexis was alone, except for a man who planned to kill her. She was alone, and it probably wouldn't be long until she was dead.

Still, a part of Alexis was surprised when she began to recognize certain landmarks. With every turn, she became more certain. And then he pointed at a white ranch house and told her to park in the driveway. It was right across the street from the vacant lot where Lucy Hayes had been found.

"Is this your house?"

He didn't answer. She remembered the people lined up along the crime scene tape. He must have been one of them. "So you live across the street from where she was found?" It sort of made sense. "What happened? Did you hear her or see her that night and come outside? Did you try to talk to her? And then something went wrong." Alexis was pulling the words out of the air, but she knew she was right by the way his face first softened and then hardened.

"Get out. And don't run or call for help. I'll be right behind you." He pushed her ahead of him, first out of the pickup and then up the walk. Together, they marched up the steps and in the front door. There was a moment where he released her arm to put the key in the lock, but by the time she realized she should ignore the gun and run, the door was swinging open and he was shoving her inside ahead of him. Her heart was beating so hard she could hear it in her ears.

The house smelled stale and somehow sad. An orange-and-white cat scampered into the living room, then skidded to a stop and did the cat version of a double take at the sight of her. It would have been funny if everything else hadn't been so grim.

"Why me?" Alexis said. "I don't understand." She was scanning the room for something she could use as a weapon. Only she found nothing. A black-and-red afghan lay folded over the end of the couch. Opposite was an old TV that probably weighed more than she did. A box of Kleenex on the coffee table. No fireplace with handy cast-iron tools. She could see partway into the small kitchen, but if there was a block of sharp knives on the counter, she didn't see it.

"Because you have that guy's DNA on you," he said. "That Nick Walker's."

"What? He's not my boyfriend or anything."

"But you are friends. And they said on TV that even a single fingerprint has enough DNA to identify who left it. I know he's their number one suspect. I watched them take the sample." He nodded at the white metal blinds. Two of them were bent back at eye level. "So I need to make sure they keep believing he's the one who killed that girl."

"You mean Lucy Hayes?" How long until Alexis was just like Lucy, lying in the cold and the dark while her life ebbed away?

He nodded. "Yes. Once another girl with that guy's DNA on her turns up dead, they'll lock him up and throw away the key."

It kind of made sense. If you were crazy. His coat flapped open, revealing a tan holster on his belt. A holster, not for a gun, but for a knife. With a horrible certainty, she knew it must be the same knife that had killed Lucy.

"Then you must not know." Alexis was thinking faster than she ever had before in her life. Was she really here, in this house that made her think of her grandmother's, trying to fool a killer? "They arrested Nick two hours ago. If I die, then the one person they'll know for sure can't have done it is Nick."

"No." He shook his head. "No."

"Yes! And as soon as a second girl turns up dead, they'll let Nick go and come looking for you."

"So what am I supposed to do? Just turn you loose?" He snorted to show how ridiculous the idea was.

"Yes. Exactly." Alexis nodded.

"I wish I could, but then you'll just go running to the police."

Alexis forced her lips into the shape of a smile. "I won't tell anyone. I promise." She tried to make herself believe her own words when she said them. Tried and failed.

He gave her a skeptical look. "Like I believe that." With the gun, he pointed at the couch. "Stop talking and sit down. I need to think."

She did. There were dozens of cat hairs snagged on the green plaid upholstery. Surely some of them were making their way onto her clothes. Maybe she should point them out. Just one more piece of evidence that would link her to this man. But would he listen? He was pacing back and forth, muttering.

She couldn't just sit here and wait to die. "I have to go to the bathroom." A bathroom would have a window. Or something she could turn into a weapon. Or maybe both.

He stopped in his tracks and regarded her with narrowed eyes. "Really?"

Alexis squirmed, doing a better job at lying this time.

"Leave your purse on the couch," he ordered as she stood up. Then he walked her down the hall. "I'm going to stay right out here. And leave the door open an inch."

Alexis walked straight to the window. It was a narrow band of gla.s.s that had been patterned so you couldn't see through it. Even if she managed to break it before he was on her, she didn't think she could squeeze through. As quietly as she could, she opened the door under the sink. She had been hoping for a can of Lysol, or some kind of toxic cleanser she could spray or throw into his eyes, but all she found was a can of Bon Ami, which had big letters proclaiming it hypoallergenic. She eased open a drawer. A cache of Avon makeup, all of it well used. So where was the woman it belonged to?

"Hurry up!" he bellowed from the hall.

She flushed the toilet and ran water in the sink without bothering to wash her hands. Maybe the police would find her DNA here as well one day. She stared at the yellow ceramic fish on the wall. Yellow circles had been attached to the wall above it as if it were blowing bubbles. Only an old lady would put that on the wall.

She threw open the bathroom door and made a run for it. Not for the front door, but for the door at the end of the hall.

"Don't go in there!" He tried to stop her, but she flung open the door.

"Help me!" she cried. "Help me!"

There was no one in the room, just a bed covered with a beautiful corduroy-crazy quilt in shades of purple and royal blue. In the corner sat a dresser topped with a TV. Next to it squatted a green machine that was like a cross between a piece of wheeled luggage and an air conditioner. It looked medical.

The man stopped at the threshold. He still held the gun, but it was no longer pointed at her.

Alexis turned to him. "Whose room is this?"

"My mom's."

"Where is she?" But she knew the answer before he said it. There was an emptiness here that was far deeper than someone having just left the room for a few hours.

"Gone." He took a deep breath. "She died."

"What happened?" Despite herself, Alexis felt a flash of sympathy.

"She'd been sick my whole life. Since I was younger than you. As a result, I didn't get to have much of a life myself. I couldn't date or anything. I don't even know how to talk to girls."

Alexis held his gaze. "You're talking to me now." And it actually was a conversation, a real conversation. Then she added, "Is this what she would want for you?" and broke the spell.

He raised one shoulder. "If it was a choice between me and you, Mom would say I should be the one to live. Sometimes we have to do things we don't want to do. Even if they're hard."

"But not this." She tried to catch his eye again, but he was no longer looking at her directly. "Not stabbing me and putting my body in that vacant lot."

"So you think that if I do that, the cops will know that Nick guy couldn't have done it," he said.

"That's right," Alexis said encouragingly. She was finally getting through to him.

"Then I guess I'll have to put it someplace they can't find it."

CHAPTER 49.

NICK.

MONDAY.