The Last Equation of Isaac Severy(57)

As the house lights came up and the theater emptied, Hazel remained in her seat. She studied the museum map, keeping her body angled toward the entrance. When the last of the children had filed out, she heard a voice behind her. His accent was thick, Spanish or Italian.

“May I compliment you on your scarf?”

She glanced over to find a spectacled man of late middle age seated in her row—the father of that family. Or had he only been sitting next to them? In his brown windbreaker and leather sandals, he looked like a European on vacation.

Hazel looked around to see if the man wasn’t addressing someone else, but they were alone.

“It really is a nice scarf,” he tried again.

“I’m not wearing a scarf.” Her hand went to her neck for confirmation.

“Herringbone, isn’t it? My favorite.”

Herringbone.

She looked at him sharply. “Mr. Richardson?”

“Ms. Severy?”

The lights cut out, and his face vanished. Music swelled as the opening credits for the next show began.

“Or is it Raspanti?” she asked over the soundtrack.

“Yes, I hope the late Mr. Richardson doesn’t mind my borrowing his name. I’m trying to keep a low profile while I’m in the States.”

“Are you even a professor?”

“I prefer mathematician. But, yes, I teach at the Polytechnic University in Milan.”

“So why are you here?”

The screen cut to black, and the film’s narration started: “Imagine Los Angeles thousands of years ago . . .”

His voice called from the dark. “Meet me near the sloths.”

When the screen lit up again, the doors were gently swinging, and Raspanti was gone.

Hazel left the theater and walked deeper into the museum. She hesitated in front of the long-limbed skeleton of Nothrotheriops shastensis: the giant prehistoric sloth. There was a large illustration of the beast on the wall, its lummox face staring out in a plea for its own extinction.

Just as Hazel was wondering if all this subterfuge was necessary, she turned to find Raspanti standing on the other side of the skeleton, peering into the blind cavities of its skull. He was quite tall, with a sharp Roman profile, like something straight off an ancient bas-relief. She understood at once that this was the man she had seen lurking that day at Isaac’s gravesite.

“Unfortunate-looking animal,” he said, pulling up the collar of his jacket, as if he believed himself to be wearing a trench coat and not a windbreaker.

In sympathy of the chill, she wrapped her cardigan more snugly around her, unsure where to begin with her line of questioning.

Raspanti leaned in a little, smelling faintly of tobacco and foreign hygiene products. “Isaac said you would make contact, but I was becoming impatient. He also said you would have something for me.”

Hazel hesitated. “An equation, you mean?”

He smiled tightly and glanced over one shoulder. “Quiet, please, Ms. Severy.”

“Even if I did have it,” she said, dropping her voice, “how do I know you’re the one I’m supposed to give it to?”

“You think I’m an impostor?” He let the accusation hang in the air for a moment. “If the watchword isn’t enough for you, it shouldn’t be too difficult for you to confirm who I am.”

As he started to turn away, she stopped him. “I searched John Raspanti. No mathematics professors came up.”

He nodded in understanding. “Your grandfather doesn’t like to make things easy, does he? He liked to call me John, but it’s Gian with a G. Giancarlo.”

Raspanti walked off, stopping a few yards away at the diorama of a Columbian mammoth, one of Hazel’s favorite exhibits. The animatronics beneath its matted fur would jerk to attention every few minutes, accompanied by a faraway roar.

She pulled out her phone and entered his full Italian name into a search engine. Up popped a portrait of Raspanti on the Milan Polytechnic site. There was also a group photo from a mathematics summit—men and women arranged Solvay Conference–style—with Raspanti towering next to her grandfather, an arm thrown around his shoulders. These were younger Raspantis, but clearly the same man who stood in front of her now.

She stepped over to the diorama.

“Why didn’t Isaac just give you the equation himself?”

Raspanti blinked rapidly. “You think I don’t ask this same question? You think I had any idea he was going to do that to himself? What I know is I get a letter in the mail one day telling me he is leaving his life’s work to me, so that ‘they’ won’t get their hands on it. He told me you would be the courier.”

“Well, he could have sent you an email attachment and saved me the trouble.”

The man frowned. “They would be looking for that. Phones are equally unsecure.”

“Who’s they?”

The mammoth rattled to life. “They are always the same: one of two groups who enjoy exploiting science for their own ends. The first group uses scientific advancement as a tool for war. The other wants to make more money than they already have. One kills, the other steals. If either group gets ahold of Isaac’s work, it would be, well, regrettable.” Raspanti dropped his voice to a near whisper. “The equation is just the beginning—a seed—for chaotic prediction. Can you imagine if the government had a formula to predict anything it wanted? Or Wall Street? You think they are going to share this formula with people like you and me?”