Thanks to Constantine Beloroutchev, for conducting key research in St. Petersburg, Moscow, and Yalta, for showing me around and advising me on all matters pertaining to the history of the period, Russian culture and language (all mistakes are mine not his); to my mother, Sally Bradby, for assistance with historical research in the UK; to my editorial team, Bill Scott-Kerr and Jason Kaufman, for their support, endless encouragement, and clever insights; to Mark Lucas, for being the greatest agent known to man; and to my inspirational wife, Claudia, for more reasons than there would be space to list.

The arctic wind sliced through Ruzsky’s thin woolen overcoat. His boots were damp and his toes numb with cold, but he was oblivious to everything except the frozen expanse before him.

All he could see was ice.

Ruzsky’s heart was beating fast. He tried to place a foot on the ice, before shifting his weight back to the step. He looked down at his boots, but his vision was blurred. He fought to control his breathing. “Christ,” he whispered. His first day back from exile and it would have to begin like this.

The constables were ahead of him, in the center of the frozen river Neva, illuminated by a ring of torches. The snowfall had tapered off through the night and the sky was now clear. The narrow spire of the Peter and Paul Cathedral on the far side of the river was bathed in moonlight.

There was a sudden flurry of movement, and a burly figure broke away from the group, the flame of his torch dancing as he walked. Ruzsky watched his partner stride toward him.

“You’re waiting for an escort?” Pavel halted, one hand thrust deep into his pocket. Small crystals were lodged in his beard and along his drooping mustache.

“No.”

“It’s the ice?” They’d had to deal with a body on the ice once before, years ago, on a small lake outside the city.

Ruzsky cleared his throat. “No,” he lied.

“It’s January. The river’s been frozen for months. If anyone was going to fall through, it would have been me,” Pavel said, gesturing to his own girth.

Ruzsky stared at him. Pavel had a round face that exuded warmth even when he was frowning. He was right, of course.

“Oh, shit,” Ruzsky muttered. He closed his eyes and stepped forward, trying to ignore the jolt of fear as his foot crunched down on the frozen surface.

“The city’s bravest investigator, afraid of the ice,” Pavel said. “Who would believe it?”

Ruzsky opened his eyes. They were walking forward briskly and he was starting to breathe more easily.

“I didn’t mean that,” Pavel said.

“I know.”

“I don’t blame you, my old friend. You’ve barely been back twelve hours and look what it has delivered up to us.” Pavel nodded in the direction of the Winter Palace. “And here, of all places.”

They walked with their heads bowed against the damp, bitter wind that whistled in from the Gulf of Finland. It was several degrees colder out here on the river.

Ruzsky thrust his hands deep into his pockets. Only his head, beneath one of his father’s old sheepskin hats, was warm.

Next to the bodies, the constables stood, smoking. They were dressed in long greatcoats and black sheepskin hats, the uniform of St. Petersburg ’s city police.

The woman was closest to Palace Embankment and lay on her back, long dark hair spread out around her head like a fan. “Torch.” Ruzsky held up his hand.

One of the men marched forward. He couldn’t have been older than seventeen or eighteen, with a pronounced nose, narrow eyes, and a nervous expression. He was lucky not to be fighting at the front, Ruzsky thought, as he took the torch and bent over the body of the woman. He got to his knees.

The victim was-or had been-pretty, though with poor skin. He removed one of his gloves and put his hand against her cheek. Her skin was frozen solid. Her face was almost peaceful as she stared up at the night sky. The fatal wound was to her chest, probably to her heart; he could see that she had lost a good deal of blood. He tried to ascertain exactly where she’d been stabbed, but her clothes were rigid and he decided to leave any further investigation to Sarlov.

Ruzsky’s hand was already numb, so he put it back into his glove and thrust it into his pocket. He straightened again, looking at the gap between the two bodies. The area around them had been well trodden by the constables, so he could make no attempt to determine a pattern of events from the footprints. “Don’t they teach them anything these days?” Ruzsky grumbled, gesturing with the torch at the trampled snow.

“It’s good to have you back.” Pavel offered him a flask.

Ruzsky shook his head. He walked around to the other body, the spitting of the flame and the crackle of his boots in the snow the only sounds above the whistle of the wind.

The man lay facedown, surrounded by a sea of crimson. He had bled like a fountain.

“Turn him over,” Ruzsky said. Two of the constables moved forward and heaved the body onto its back.

Ruzsky breathed out.

“Holy Mother of God,” Pavel said.

There were stab wounds to the man’s chest and neck and face, one through his nose, and another peeling back his cheek.

“Who were they?” Ruzsky asked.

“I don’t know.”

“Have you checked their pockets?”

“Of course. Nothing, except this.” Pavel handed over a roll of banknotes-small denomination Russian rubles.

“That’s it? No identity papers?”

“Nothing.”

“Cards? Letters?”

“There’s nothing.”

“Have you looked properly?”

“Of course I have.”

Ruzsky bent down and pulled back the man’s overcoat. He thrust a gloved hand into the inside pocket. It was empty. He straightened again and shoved the roll of rubles into his own coat. “The girl?”

“Same.”

“Any sign of a knife?”

“No.”

“How far have you looked?”

“We were waiting,” Pavel said slowly, “for you.”

The constables started to move about again. “Stay where you are,” Ruzsky instructed them. He walked back to the girl. As he looked down at her, he felt suddenly sober. She was young, probably no more than twenty; well dressed, too. They both were. It was difficult to be sure, but he didn’t think she had been stabbed more than once. He looked across at the other body. They were about seven yards apart.

“You’ve checked all of their pockets?”

“Twice.”

“We’ll have a look when we get them inside,” Ruzsky said, mostly to himself. He didn’t want to take his gloves off again out here.

Ruzsky looked up toward the Admiralty spire above Palace Embankment, and the golden dome of St. Isaac’s Cathedral in the distance. They were in full view of the austere blue and white facade of the Tsar’s Winter Palace, but at a distance of fifty yards or more. Pavel followed his gaze.

“Perhaps a servant saw something,” Ruzsky said.