How did he know about her head injury? Had she told him? She couldn't remember. Maybe it had been on the news. Or maybe he meant her old head injury, from the mugging. 'It's OK. No big deal.'

Silence while she sipped tea.

Ron watched her, grim-faced.

'Really. Thanks for caring. I'm fine.'

Ron looked away. Sipped his Martini. 'So. Any idea who the guy is?'

'Not who.' Harper lowered her voice. 'But I think I know why.'

'Really?' Ron's eyes riveted hers.

She leaned forward, closer to him. 'Those drugs. It has to be. First, the guy mugged me. He must have thought they were in Graham's bag. But he didn't find them there, so he searched my house. And, again, he found nothing. So he still thinks I have them-'

'But Harper, a whole bin of drugs was stolen. They wouldn't fit in a book bag.'

Harper was unfazed. 'But some of them would.'

Ron looked doubtful.

'OK, I don't know exactly what he wanted a the actual pills or money for them or what. But it was something to do with the drugs. I'm sure of it.'

Ron pursed his lips, thinking. 'Except for one thing.'

'What?'

'Let's say you're right, and Larry, Graham and Monique stole the drugs. Graham was already dead. So who killed Larry and Monique?'

Good point. Someone else had to be involved.

Ron cleared his throat. 'Harper. Leave it alone. There's more to this than you're aware of.'

More? Harper's pulse picked up. She heard a bang and looked up, expecting to see pieces of Marvin. But all she saw was Ron, his liquid, golden eyes.

As if on cue, the waiter appeared to take their orders.

'How about a steak?' They hadn't even glanced at the menus.

Harper shrugged. She wasn't hungry, didn't care about food. She wanted to hear what Ron had to say.

Ron ordered. The waiter left, and Harper waited for Ron to pick up where he'd left off. He didn't. She had to ask. When she did, Ron took a swig of his Martini before answering.

'I'm trying to decide how to phrase it. But I can't think of a delicate way, so I'll just say it. Our research indicates that, in extremely rare and unlikely circumstances, the missing drugs can have unanticipated adverse side effects.'

Harper sifted through syllables to grasp Ron's meaning. Side effects? 'But you said the pills were benign.'

'Absolutely. In proper dosages. But-'

'What kind of side effects?' In the dim light, Ron seemed fuzzy, as if his skin lacked definition; as if he might fade into darkness.

Ron drew an audible breath. 'Let me explain. This drug works by stimulating specific parts of the frontal lobe. In trials, that stimulation has significantly enhanced memory and facilitated several processes involved in learning. In short, it's proved to be a miracle drug.'

He paused.

Harper waited. Bottom line, the drug helped memory and learning. She'd already known that. 'The side effects. Tell me.'

'Well, that's just it. In normal dosages, when the drug is taken for limited durations, there don't appear to be any side effects at all. It's only when it's taken in large doses or over extended time periods that undesired effects might arise. Mind you, they don't always arise. But testing has shown that the drug can over-stimulate the hippocampus.'

The hippocampus? Harper tried to call up fifteen-year-old information from her undergraduate psychology classes. No luck. She had no idea what a hippocampus did. But she didn't want to sound stupid, so she didn't ask.

Instead, she asked, 'Causing what to happen?'

'Let me repeat.' Ron leaned across the table; his voice was hushed. 'The side effects appeared only rarely when the drug was taken in large dosages or over an extended period of time.'

Harper waited. 'What are they?' Why wouldn't he just tell her? Were they so horrible?

Ron faced her, met her eyes. 'The hippocampus. Do you know anything about it?'

'Just that it's part of the brain.'

'Well, in part, the hippocampus is known to regulate impulsive behavior.'

He waited, watched Harper's face, making sure she was following.

'Normally, the mature brain engages many processes to evaluate behavior, envision consequences and overcome impulsive drives. But abnormally high activity in the hippocampus can override those processes, resulting in excessive impulsive behavior, even violence.'

He paused again, letting the information sink in.

'For example, mapping the brains of serial killers typically shows extremely high activity in the hippocampus.'

Oh dear. 'So, if some thrill-seeking kids steal it and pop a handful at a time, thinking that if a little is good, a lot will be better, then-'

Ron nodded. 'Exactly.'

Harper didn't finish. They both knew what she'd been about to say: those thrill-seeking kids would be at risk of side effects causing impulsive, possibly violent behavior. 'Oh God.'

'Now, Harper.' Ron leaned on his elbows. 'Let's keep a perspective. This drug isn't unusual; large dosages of many common FDA-approved drugs can be harmful.'

'Harmful, in that they cause impulsive violent behavior?'

'Even worse. Some a like common sleeping and pain pills a can kill people.'

'So can impulsive violent behavior like jumping out a window.'

Ron didn't answer. He examined his fingernails, avoiding her eyes.

'And how about what happened to the waitress? Could those drugs cause someone to commit rape and murder? You think that's what happened? Someone took too many pills and killed the waitress, and Larry and Monique?'

Harper fired questions at Ron, but his gaze remained fixed on his hands, and she wasn't surprised when he didn't answer.

Harper's eyes were on Ron but she wasn't seeing him. She was seeing Graham impulsively and violently flinging himself out the window. He'd had an open vial of the experimental drug in his book bag. Who knew how many he'd taken? Maybe he'd swallowed a handful, thinking they'd help him with his quiz.

Instead, the pills had caused impulsive violence. In the form of his suicide.

Harper leaned back in the booth, her shoulders suddenly less tight, her breathing slower. Oddly, she felt relieved. But why? Nothing had changed: Graham was still dead, the waitress still a victim of rape and murder, and Larry and Monique still lying on slabs in the morgue. The missing pills were still out there for other unsuspecting people to swallow. Even so, Harper felt lighter, more optimistic than she had all week. The violence erupting all around her wasn't the work of some depraved, deliberate serial killer. It was accidental, the result of a drug-induced chemical imbalance in someone's brain. It was synthetic, stoppable. Not truly evil. And her reaction was palpable; a ripple, something like giddiness, rose inside her. When the steaks arrived, Harper dug in, suddenly starving, slicing through tender meat, soaking up blood-red juice with potatoes au gratin.

'So you can see a' Ron chewed a 'it's imperative that we find the missing drugs.'

Right. It was very imperative.

'We can't let any more of these mishaps occur, especially not at this late stage in the trials.'

Wait. 'You're continuing the trials? With what you know?'

'Of course we are. Harper. Used as directed, this drug will help patients with learning disabilities, brain injuries, certain forms of dementia. It will dramatically enhance memory and learning capabilities. Its benefits are broad and significant-'

'Unless someone takes too much and kills somebody?'

'If you took too much aspirin, you'd die, too. Too much anything can kill you.'

He was right. Too much anything, including red meat. Harper cut another chunk, savored the texture, the richness of prime beef. The waiter brought a bottle of red wine. Candles flickered, cast a golden glow on to the palette of Ron's face; darkness and light impishly danced on skin. What was she doing here with him? Couldn't he have told her about the pills on the phone?

She watched his fingers deftly working his utensils, his jaw flexing as he chewed. Rippling his cheek muscles. He smiled, suddenly, aware of her stare. 'What?'

'Nothing.' She looked away.

Ron put down his fork, studying her. Then, reaching across the table, he touched her arm, held it. 'This has been an ordeal for you. But, from what I've seen, you've handled it with incredible grace and strength. Thank God that, in spite of everything, you're all right. Except for that nasty lump.'

The lump again. Harper couldn't remember telling him about it. She must have, though.

'. . . you can think of?'

She'd missed the first part of his question.

'Think for a minute,' he went on. 'Do you still have anything of Graham's at all?'

Of course she didn't. 'Nothing.' Well, except for that scrap of paper with scribbled numbers on it. Larry had said that it was a study guide. The numbers probably weren't important. Still, maybe she should mention it. Maybe Ron would know what they were. 'All I can think of is that list of numbers.'

He released her arm. 'I should take a look at it. Just in case.'

Harper stiffened; the timbre of Ron's voice had changed. 'Just in case?'

'In case it's important. Look, I don't mean to be an alarmist, Harper. Whatever the guy who tossed your house is looking for, he's killed people trying to get it.'

Ron was warning her that she could be next. That she was in danger. Sameh entered the restaurant, approaching them, smiling. Oh God. Not now. Harper looked for a lemon, grabbed the twist from Ron's empty Martini glass and shoved it into her mouth.

'Harper?'

Eyes closed, she munched on the lemon rind, concentrating on the tang. The intensely sour, bitter flavor.

When she opened her eyes, Ron was watching her. Thank God, Sameh was nowhere in sight.

Ron finished his last bite of steak, put his fork down and leaned back. He looked worn out. 'Who'd have thought a wonder drug could cause so much trouble?'

Harper had no answer. In her experience, trouble popped up all over the place. Why not from a pill bottle? She swallowed the last of her potatoes.

Ron sighed. 'Well. There's no option anymore. I'll issue a press release about the theft. Give the serial numbers of the missing pills and vials. Warn people not to buy or take them. It might ruin our trials, but I don't see any way around it.' His mouth formed an unconvincing smile.

This time, Harper touched his hand. It was smooth, strong. Her fingers felt comfortable there, wanting to remain. 'People have died, Ron. Others are in danger. It's the right thing to do.'

He met her eyes and the skin of Harper's fingers tingled.

'It's late,' Harper made herself say. 'We'd better go.'

He didn't say anything, just kept looking at her. Harper looked back. His stare was intense, probing. She returned it, oddly engrossed, examining his features. They were symmetrical, delicate but still manly. And his lips a oh dear. They looked soft and plump. Probably, he was a slow and tender kisser, the kind who slides and slips, gently pressing and releasing. She could almost feel it. But Ron stood, offering not his lips but his arm to escort her out of the restaurant. Wow! Where was her mind going? She needed to get out of there, to get a grip.

Harper didn't look at Ron or speak until they got to his car and drove off. And, then, all she said was that her house was a crime scene, so she wasn't going home. She'd begun giving him directions to Vicki's when Ron pulled off the road and stopped.

'Come to my place.' His eyes pierced hers, and his voice was throaty, like sex. 'Stay with me.'

'What?' Stay with him? Really? 'I can't.'

'Of course you can. Look, this is serious, Harper. I'm not propositioning you; I know you're married. But your husband isn't able to be there for you, and you shouldn't be alone. There's a killer out there, and I . . . Hell, I want you to be safe.'

Ron's gaze was warm. Or something was; Harper felt heat welling up around her. He smelled of spice and booze and work and musk, and he covered her hand with his. His touch was no longer strange.

'I promise, I won't make a pass.' His eyes twinkled softly and his lips teased with a playful smirk. 'Unless you want me to.'

God forgive me, Harper thought. Because, at that moment, she wanted him to, very badly. Her skin throbbed where he touched it. And where she imagined him touching it. Even so, something held her back. No matter how intoxicating Ron's scent, no matter how seductive his touch, the man simply was not Hank.

But Hank might have cheated on her. And he wasn't able to be with her. And he might not ever be able to, no matter how badly she needed him or how much she wished otherwise. Ron, on the other hand, was right there. With his gentle caring hands and thick voice and knowing, glowing eyes and smooth, smooth skin. He was there.

But no. No.

Later, as she lay down on sheets perfumed with fabric softener in a room filled with air freshener, Harper replayed the scene again and again, hearing Ron inviting her to stay with him. And no matter how hard she tried to stop, no matter how she tried to replace his image with thoughts of Hank, Harper lay awake, tossing, wondering what would have happened if she'd agreed and gone.

Sleep simply wasn't going to happen. Harper fluffed pillows, turned from one side to the other. Tried to read a TIME magazine she found on the nightstand, but couldn't focus on the page. Switched on the television, found the noise, the commercials irritating.

Finally, she got out of bed and wandered around Vicki's guest room, feeling trapped and edgy. She looked out the window. The police cruiser had gone, and she gazed into the trees, wondering if the killer might be watching her, still convinced that she had some connection to the stolen drugs. Nothing moved outside; the night air was still and undisturbed, revealing no sign of a trespasser. Harper moved away from the window, sat on the bed. Saw her bag on the dresser beside Hank's computer. And remembered the page of numbers. She'd forgotten to show it to Ron.

Maybe, if she looked at it again, she could figure out if they stood for anything. Assuming they weren't a study guide, maybe they were some kind of code. Opening her bag, she felt around for loose papers, found some receipts for groceries and stamps, to-do lists she'd made and abandoned. But no page of numbers.

Damn. It was in there, somewhere. It had to be. She dumped her bag out on to the bed. Found the usual: keys, extension cord, change purse, wallet, pens, notebooks, folders, grade book, flashlight, textbook, tampons, hairbrush, baby wipes, chap stick, tweezers, toothbrush, forms for the copy machine, candy bars, water bottle, antibiotic cream, lip balm, Swiss army knife, sunglasses, stapler, Tylenol, plastic spoon, corkscrew a Lord, was there no end to the stuff this bag could carry? Paper clips. Nail clipper. Two Tide sticks. Sewing kit. Sun screen. Memo about a department meeting. Baseball cap. More baby wipes. Band-Aids. Out-of-date coupons for shampoo, toilet tissue and Parmesan cheese. Old birthday card from her mother. Receipt from her last physical.

But no sheet of paper with numbers written on it.

Harper sat on the bed, puzzled, staring at the small mountain beside her. It had to be here. It had been there earlier; she'd seen it when she'd called for help. Damn. Where was it? Had she inadvertently stuck it in a folder? She rifled through them, the textbooks, the grade book. Nothing. She knew she hadn't tossed it out. But had she accidentally dropped it? Not noticed it floating to the ground?