“There was a riot at some poetry meeting!”

“I bet she went to Mayakovsky Square. If that’s all . . .” He did not know everything his sister got up to, but he suspected her of worse than poetry.

“You have to do something, Dimka! Before they . . .”

“I know.” Before they start to interrogate her, Mother meant. A chill of fear passed over him like a shadow. The prospect of interrogation in the notorious basement cells of KGB headquarters terrified every Soviet citizen.

His first instinct had been to say he would get on the phone, but now he decided that would not be enough. He had to show up in person. He hesitated momentarily: it could harm his career, if people knew he had gone to the Lubyanka to spring his sister. But that thought barely gave him pause. She came before himself and Khrushchev and the entire Soviet Union. “I’m on my way, Mother,” he said. “Call Uncle Volodya and tell him what’s happened.”

“Oh, yes, good idea! My brother will know what to do.”

Dimka hung up. “Phone the Lubyanka,” he said to Vera. “Tell them very clearly that you’re calling from the office of the first secretary, who is concerned about the arrest of leading journalist Tanya Dvorkin. Tell them that Comrade Khrushchev’s aide is on his way to question them about it, and they should do nothing until he arrives.”

She was making notes. “Shall I order up a car?”

Lubyanka Square was less than a mile from the Kremlin compound. “I have my motorcycle downstairs. That will be quicker.” Dimka was privileged to own a Voskhod 175 bike with a five-speed gearbox and twin tailpipes.

He had known Tanya was heading for trouble because, paradoxically, she had ceased to tell him everything, he reflected as he rode. Normally they had no secrets from one another. Dimka had an intimacy with his twin that they shared with no one else. When Mother was away, and they were alone, Tanya would walk through the flat naked, to fetch clean underwear from the airing cupboard, and Dimka would pee without bothering to close the bathroom door. Occasionally Dimka’s male friends would sniggeringly suggest that their closeness was erotic, but in fact it was the opposite. They could be so intimate only because there was no sexual spark.

But for the past year he had known she was hiding something from him. He did not know what it was, but he could guess. Not a boyfriend, he felt sure: they told each other everything about their romantic lives, comparing notes, sympathizing. Almost certainly it was political, he thought. The only reason she might keep something from him would be to protect him.

He drew up outside the dreaded building, a yellow brick palace erected before the revolution as the headquarters of an insurance company. The thought of his sister imprisoned in this place made him feel ill. For a moment he was afraid he was going to puke.