Vasily Ustinov was her second in command at the institute, though he didn’t look it. He wasn’t the type who lived in his lab coat, nor did he sport the brown-corduroy-with-elbow-patch look other senior government scientists were fond of.

He’d grown up in the Caucasus and had an unruly mane of black hair and an even more unruly beard. It made him look like a cross between Che Guevara and Jack Sparrow. He gave the impression of knowing his way around a Kalashnikov. Traveling with him to a climate conference in Sweden a few years earlier had been a lesson in airport security profiling.

Despite all that, he was the best anthrax specialist the country had produced in a generation.

“We’re sixteen hundred miles from the nearest airfield,” Sofia said.

“And if anything goes wrong, they’ll come right for us. We’re their top priority,” he said.

She nodded.

The truth was, it wasn’t the remoteness that was bothering her. It was the nature of the mission. No one became a doctor because they wanted to kill people.

She and Vasily were in the front vehicle, and behind them were four more scientists from the institute, along with twelve armed soldiers who’d been assigned as their security detail. She had no idea what the soldiers were supposed to be protecting them from. Neither did they, it seemed.

“They’re watching us,” Vasily said when he first saw them. “Making sure we don’t do anything … unpatriotic.”

Sofia knew he was right.

From Yakutsk, they’d been ferried north along the Lena River on a military barge, the hull of which could withstand impact with ice three feet thick. That was reassuring. For someone in charge of daring scientific expeditions, Sofia was surprisingly timid around open water.

And the river was vast even by Siberian standards. Over five miles wide at places, it was unspanned by any bridge. The barge took them north as far as the Vilyuy tributary, where Sofia was glad to plant her feet on the solid, shaley beach of the river’s east bank.

They were deep in the territory of the Sakha Republic, one of twenty-two republics recognized within the Russian Federation. It covered more than a million square miles, about a third the size of the contiguous United States, and in all that space there was only a single city, Yakutsk, which battled with Norilsk for the title of coldest on earth.

The terrain was continuous permafrost, land that, unlike the rest of Eurasia, hadn’t thawed at the end of the last ice age. For centuries, trappers and explorers had been finding the remains of strange, long-extinct creatures there. In the thawing permafrost, they found perfectly preserved steppe ponies, mammoths larger than any living land animal, and wooly rhinos with horns over a meter long.