“I started at eight and finish at six,” he told her, glancing around. “I’m not supposed to chat while I’m on duty.”

“How is Annushka?” Maria continued. “I haven’t seen her in ages.”

“I don’t know where she is. She’s left home. I haven’t heard from her.” He couldn’t meet her eye and she knew he was lying.

“Oh dear, I hope she’s all right. Do give her my regards if you see her.” Maria smiled and walked past, as if simply going about her business.

At six that evening, she huddled in a doorway of the Admiralty building on the other side of Nevsky Prospekt, waiting to see which way Fedor would head. He crossed to a tram stop heading into town and waited there, stamping his feet against the cold. When she saw a tram approaching, Maria pulled her scarf tight around her head and scampered across the road just in time to jump on the back. She stood behind a large man in workers’ overalls as the tram headed out toward the suburban districts.

When Fedor alighted, Maria jumped off too, turning as if to walk in the opposite direction then checking over her shoulder. He didn’t look around as he crossed the street and headed into a park. She hurried after him and saw him emerge through a gate on the other side. He stopped by a bread shop, which was closed for the night, and hammered on the door. After a while a woman opened it and handed him a loaf wrapped in paper. He must be a regular.

At last he stopped outside an apartment building. Maria was on the opposite side of the road so couldn’t see which bell he rang, but on the third floor a curtain twitched and she saw a face looking down. It was Annushka. She was sure of it. Fedor entered the building.

Maria crossed the road and waited till someone else opened the street door, then rushed forward to catch it before it slammed. She walked up the concrete stairs, similar to her own, all the way to the third floor, and estimated which door it must be: second along from the main stairs. Thankfully these blocks were built to a uniform pattern.

Fedor opened the door and gawped at her. “What on earth are you doing here?”

“Can I come in?” Maria asked. “I’m here to see Annushka.”

He hesitated, then stood back to let her pass. Annushka gasped and clutched her young son to her side as Maria walked into their sitting room.

“How did you find me?” she asked.

“Very easily,” Maria told her, looking at Fedor. “And Yuri could do the same anytime. If you want to avoid him, you will have to do better than this.” She sat down before explaining that he had asked her to look for them.