“Yes, but bad cake?”

“The real brain food. And to think my doc always told me to take fish oil for brainpower.”

“Supposedly, these kids will rule the world.”

Nina laughed. “Hardly, Sandy. They’re mathematicians. It’s not like they study law or anything useful.” She bit into a gusher of grease. “Let’s start with the Herr Professor.” Drinking the last of her cola, she repressed a burp, consulted her watch, picked up the phone, and punched a number. “The direct method. A times B equals MIT.” Nina pressed the speaker button so that Sandy could listen to the ringing.

A brusque voice answered. “Braun.”

“How do you do? My name is Nina Reilly. I’m a lawyer, calling from California on an important matter.” She was grinning, feeling cocky. It must be the liverwurst.

“Oh? What can I do for you, ma’am?” Herr Professor didn’t have a trace of an accent.

“I’m looking for some witnesses in a legal case here. One or more of the witnesses may be students of yours. May I give you some descriptions, and ask you if any of them sound familiar?”

“What kind of legal case?”

“A wrongful-death case. A woman was shot two years ago here at Lake Tahoe, and the students were witnesses.”

“Information about our students is confidential.”

“Of course. But perhaps you could confirm the existence of such students, as a matter of public duty. I’m not asking for anything else. The first one is an Indian. Of East Indian heritage, that is. He has thick black hair and a nice smile, and his eyebrows grow together in the middle.” She went on with the description of the most memorable of the three witnesses, sounding perfectly calm. Sandy sat next to her, her bracelets jangling slightly as she wrote on the pad.

“You think he’s one of my students?” Braun said when she had finished.

“That is my information. He’s interested in, er, the Riemann Hypothesis, I believe. Possibly.”

“And what would you do with him if you found him?”

“Ask him to come back to California for a deposition. All expenses paid.”

“And if he didn’t want to come?”

“That would be a problem,” Nina said. “The witness-subpoena power does not extend beyond the state boundary.”

“So he could refuse and you would not bother him anymore?”

“I would have no power to compel him to come here as a witness,” Nina said. Sandy frowned at this circumlocution, and Nina winked at her. “Rest assured, Professor Braun, that I would not bother him if this were not necessary to right an injustice.”

“Who did you say you were?”

“Nina Reilly. A California attorney.”

“Give me your state bar number.” She gave it to him. She wasn’t grinning anymore.

“I’ll look into it,” the professor said.

“A woman was killed,” Nina said. “This young man needs to step up and tell what he knows about it.”

“I have your number in the memory. Good-bye, ma’am.” He hung up.

“Is he gonna help us or not?” Sandy asked.

Nina tapped her temple. “Even great minds may err, Sandy. He’s cautious, and that may outweigh his sense of civic duty.”

“So are you gonna wait to hear back?”

“Book me on United to Boston for tonight out of Reno, would you?”

“Done.”

“What have we got this afternoon?”

“The DMV. The lady whose boat dropped off the trailer onto the freeway. Roberta. You ought to be finished by four.”

“Then I’ll run home and get Bob over to his uncle’s house and pack a bag. And please call Chelsi Freeman. I can’t make the massage appointment this afternoon.”

“What else should I do? When are you coming back?”

“After I have talked to those witnesses.”

“I’m not even going to ask who is going to pay for this trip.”

“What are credit cards for?” Nina said.

14

HER OPTIMISTIC MOOD LASTED THROUGHOUT THE flight from Reno. She loved red-eye flights anyway, sitting in the window seat, watching dawn suffuse the sky, her beam of light trained on the material she was reading while the other passengers dozed uneasily beneath their inadequate blankets and the flight attendants gossiped in the back.

She was coasting on a strong sense of determination, of being on the hunt. She’d never need to sleep again. She would find her witnesses. She was sure of it.

She had brought piles of printouts Sandy had pulled off the Web concerning the two hypotheses, the state of mathematics these days, and MIT information. Packed in her carry-on were also the police reports on Sarah Hanna’s death, a small tape recorder, and her laptop. There had been just enough remaining room for two pairs of underwear and her curling iron.

Nina read, making notes with her right hand, doodling, generating lists and plans.

By 9:00 A.M. on Friday morning Nina was washing her face in her room at the Charles River Inn. Outside, sloping uphill from the muddy river, spread the curiously European village of Cambridge, Massachusetts. The iviest of the ivy-covered brick campuses of the Northeast, which Mick called the Big H, was six blocks up the street, past Harvard Square and the Red Line subway station. MIT was a few miles’ drive along the river, or a stop or two on the Red Line.

She took a taxi up Memorial Drive. On this winter’s morn, sculls skidded through the icy water and boys and girls rushed along the banks as they had for about four hundred years. Bright sun blessed the bridges with golden light, sweetly disguising decades of gray grime. The venerable brown city of Boston loomed on the other side of the river, dry air sharpening the skyline, but even a clean hint of coming frost in the air couldn’t entirely subdue the reeking diesel and industrial smells.

Lake Tahoe Community College had a serene woodland setting, with low California buildings. At MIT, islands of grass, brown at this time of year, were pitifully dwarfed by many-storied concrete stacks engineered by maniacal purists. One did not major in phys ed or English literature at MIT, as one might choose to do at Tahoe. One majored in science, any science. The older Greco-Roman style buildings, nods to classical academia, had in the last century given way to functional beige buildings that housed sharp minds who found beauty in things less evanescent than mere aesthetics.

Lack of sleep and her ongoing self-assured mood had made Nina bold. “I need Professor Braun,” she told the male receptionist at the math department. “Room 2- 181.”

The boy, who appeared to be just a few years older than Bob, said, “Professor Braun’s already gone for the weekend. Sorry.”

“Oh, no! I really hoped to tell him some exciting results I have-this work I’ve been doing using Fourier inversions. I met him in Palo Alto at the American Institute of Mathematics a couple of years ago, and he was very interested in my work.”

“The Riemann seminar?”

“Right! I’m from Stanford. Had to come to the East Coast for a wedding and stopped off here. I really need to talk to him.” She clutched her briefcase to her chest and allowed herself to look slightly desperate, as though the nonexistent equations might be unraveling as they spoke.

“I’m sorry, but he’s home in Newton. I can’t give out his address.”

It was a blow, but Nina had fallbacks ready.

“How about his student? You know, the guy who was going out with that pretty German girl, or was she Norwegian? He was Indian… I forgot his name…”

“Raj attended that seminar?” His voice was mildly curious. “I didn’t know he had the interest.”

A little thrill went down her back. “Raj. Yes, that’s him. Any idea how I could get hold of him?”

“He’s probably drinking coffee at the student center right about now. With the lovely Silke sitting devotedly by his side, lucky man.”

Hot ziggety dog, Nina told herself. “Silke. That’s his girlfriend, right? He talked about her.”

He nodded. “You know, I applied to Stanford but couldn’t turn down MIT. Man, I regret it every single time I have to put on a coat, hat, boots, and gloves just to go outside to pick up the newspaper off the front step. So you’re a number theorist? An instructor there?”