For the first time Erik noticed twelve riflemen standing on the lip of the ravine, among the trees. Twelve prisoners, twelve riflemen: he realized what was happening here, and incredulity mixed with horror rose like bile inside him.

They raised their guns and aimed at the prisoners.

‘No,’ Erik said. ‘No, you can’t.’ Nobody heard him.

A woman prisoner screamed. Erik saw her grab the eleven-year-old boy and clasp him to herself, as if her arms around him could stop bullets. She seemed to be his mother.

An officer said: ‘Fire.’

The rifles cracked. The prisoners staggered and fell. The noise dislodged a little snow from the pines, and it fell on the riflemen, a sprinkling of pure white.

Erik saw the boy and his mother drop, still locked together in an embrace. ‘No,’ he said. ‘Oh, no!’

The sergeant looked at him. ‘What’s the matter with you?’ he said irritably. ‘Who are you, anyway?’

‘Medical orderly,’ said Erik, without taking his eyes off the dread scene in the pit.

‘What are you doing here?’

‘I brought an ambulance for the officers hurt in the collision.’ Erik saw that another twelve prisoners were already being marched down the slope into the quarry. ‘Oh, God, my father was right,’ he moaned. ‘We’re murdering people.’

‘Stop whining and fuck off back to your ambulance.’

‘Yes, Sergeant,’ said Erik.

(iii)

At the end of November Volodya asked for a transfer to a fighting unit. His intelligence work no longer seemed important: the Red Army did not need spies in Berlin to discover the intentions of a German army that was already on the outskirts of Moscow. And he wanted to fight for his city.

His misgivings about the government came to seem trivial. Stalin’s stupidity, the brutishness of the secret police, the way nothing in the Soviet Union worked the way it was supposed to work – all that faded away. He felt nothing but a blazing need to repel the invader who threatened to bring violence, rape, starvation and death to his mother, his sister, the twins Dimka and Tania, and Zoya.

He was sharply aware that if everyone thought that way he would have no spies. His German informants were people who had decided that patriotism and loyalty were outweighed by the terrible wickedness of the Nazis. He was grateful to them for their courage and the stern morality that drove them. But he felt differently.

So did many of the younger men in Red Army Intelligence, and a small company of them joined a rifle battalion at the beginning of December. Volodya kissed his parents, wrote a note to Zoya saying he hoped to survive to see her again, and moved into barracks.

At long last, Stalin brought reinforcements from the east to Moscow. Thirteen Siberian divisions were deployed against the ever-nearer Germans. On their way to the front line some of them stopped briefly in Moscow, and Muscovites on the streets stared at them in their white padded coats and warm sheepskin boots, with their skis and goggles and hardy steppe ponies. They arrived in time for the Russian counter-attack.