‘I see,’ he said again.

She wondered if he did. She pressed his hand to make him look directly at her, and when he did she wanted to tell him that she was just as frightened as everyone else and she didn’t blame any of them for keeping their mouths firmly shut. She wanted to say that having Chang An Lo here in Moscow made her come alive for the first time in months, but at the same time she was seething with rage at the Soviet watchers for making it so hard for them to be together. She wanted to tell Alexei that having her brother here in her room made her feel safe, even though he was in a worse state than she was. But what about their father? What kind of world was he in? Was he surviving? How in this twisted and secretive city would they ever be able to find him? Tell me how. How? Yet when she looked into Alexei’s eyes, which used to be green but now were the colour of mud, she said none of it.

Instead she smiled at him. ‘I’m so pleased you’re here, as safe and as handsome as ever under all that filth.’

‘ Thank you, Lydia. You know I wouldn’t abandon you to do this alone.’

She felt two hot tears trickle down her cheeks. Alexei brushed a thumb lightly along her cheekbones, wiping the tears away with an affection that she knew she didn’t deserve after all the times she’d sworn at him behind his back.

‘I’m happy,’ he said, ‘to see you happy.’

She was just working out whether he meant it or was just trying to please her, when a heavy fist banged on the door. Twice. They froze, his thumb still on her skin, her fingers still clasping the hand on her knee.

‘No,’ she whispered. ‘No.’

Quickly she bundled her brother back into bed, pulled the blanket up to his ears and tucked it tightly round him.

‘Don’t move,’ she hissed.

Then she opened the door.

Outside on the landing stood three men. Lydia took one look at them and slammed the door in their faces.

‘Who is it?’ Alexei was struggling up in the bed.

‘It’s bad news.’

‘Police?’

‘No.’

‘Who, Lydia? Tell me.’

She had her back pressed to the door, breathing hard. ‘They look like killers.’

Alexei tumbled out of bed and moved close to the door, listening. The fist slammed on the door again, three bangs this time.

‘Alexei Serov,’ a rough voice called out. ‘Open this fucking door or I’ll kick it down.’

Lydia stared in horror at Alexei. ‘They know you. Who are they?’

Alexei leaned round her, took hold of the doorknob and clicked the door open. ‘My dear sister,’ he said with a smile so crooked it made him look like a stranger, ‘I’d like you to meet my new friends.’

‘They took him away. In a car.’

‘They’re welcome to the bastard.’

‘Liev,’ Lydia snapped, ‘shut that foul mouth of yours.’

The big man laughed. Elena smacked him. ‘So who the hell were these people?’ she asked. She was more agitated than Lydia expected.

‘I don’t know,’ she moaned. ‘They were rough. Shabby but wore good boots.’

‘You noticed their boots?’

Lydia shrugged. Yes, she noticed boots. They told you more about what lay in a man’s wallet than any amount of furs on his back.

‘They had hard cold eyes and hard cold smiles.’

‘But were they his friends?’ Elena asked. ‘He told you they were his new friends.’

‘They were no more his friends than rats are friends to day-old chicks.’

‘Did they give any idea where they were taking him?’

‘No.’

‘Did he look frightened?’

‘Alexei would never let it show if he were.’ Lydia thought back to it, pictured for the hundredth time Alexei’s expression as he walked out of the door. His back was straight, his stride stiff-legged, and he reminded her of dogs that circle each other, bristling, before hurling themselves at each other’s throats. She shivered.

‘Elena, I can’t lose him again.’

Liev’s teeth flashed somewhere in the depths of his black beard. ‘Don’t fret, little Lydia. It’ll take more than a rat or two to kill off that bastard brother of yours.’

‘There’s something else.’

‘What?’

‘I remember that one of them wasn’t wearing gloves. He was standing in the doorway with hands stuck in his coat pockets, watching the corridor.’

‘So?’

‘So I was scared he’d have a gun in there. But just as the other two were walking out with Alexei between them, this man took his hands out of his pockets and they were empty. But I saw right across his middle fingers he had dark tattoos.’

Nobody moved. Nobody spoke. It was as if the room had splintered.

‘What?’ Lydia demanded. ‘What is it? What have I said?’

‘Tattoos,’ Popkov growled.

‘Yes.’ Lydia seized his massive arm and shook it hard. ‘What does it mean?’

Elena and Popkov exchanged a look. Lydia ’s pulse was suddenly pounding, a noise like water rushing through her brain, flushing away her control.

‘Who are they? Who are these rats?’

Elena’s face changed. Her concern was replaced by disgust and her fleshy mouth twitched with distaste. ‘It’s the vory v zakone,’ she muttered. ‘He’s in with the vory.’

Those words – vory v zakone – Lydia had heard them before. From the girl on the train.

The Cossack sank down on Lydia ’s narrow bed, making its metal frame yowl like a tomcat. ‘The vory,’ he muttered, sighing out a great rush of stale air. ‘He’s a dead man.’

Lydia thought she’d heard wrong. She could feel the spaces in her chest trembling and it seemed to shake the whole house.

‘Tell me, Liev, exactly who these vory v zakone are.’

‘Criminals.’

‘A criminal brotherhood,’ Elena explained.

Lydia sat herself down beside Popkov on the bed. ‘Tell me more.’

‘They use tattoos all over their bodies to show allegiance. The vory v zakone, thieves-in-law, is what they call themselves. I’ve come across them before. It started in the prisons and labour camps, but now they’re all over the cities of Russia like a fucking plague.’

‘Why would they want Alexei? He’s not a thief.’

Popkov grunted and offered no answer. Lydia leaned against his arm as though it were a wall. ‘Why the tattoos?’

‘Apparently each tattoo means something,’ Elena said. ‘It’s like a secret language within the brotherhood. And just the sight of the tattoos warns people off.’

‘Are they dangerous?’

They hesitated. It was slight, but she didn’t miss it. Then Popkov clapped her on the back with his great bear’s paw, which made her teeth sink into her tongue. She sucked the blood off it.

‘Come on, little Lydia,’ Popkov frowned at her, ‘you don’t need him. We manage well enough without this brother of yours.’

His eyebrows, thick as black beetles, descended above the broad bridge of his nose, and he only just raised his arm in time to ward off her punch to his face. With a growl he wrapped both his arms around her slight frame so that she couldn’t move. She sat with the weight of her head on his chest and started at last to think clearly.

‘If he’s with these criminals, these vory,’ she said into his stinking coat, ‘the boy will know. Edik will have an idea where to find them.’ She wriggled free and jumped to her feet. ‘Elena, I’m going to need some sausage for the dog.’

Edik, where are you?

Lydia was running down the stairs when the front door opened. The concierge had scuttled across the hallway with the movements of an arthritic mouse to do her duty. She made a note of the visitor’s name, and darted out of sight back to her mousehole at the rear of the house with a speed that should have alerted Lydia. But she was preoccupied, working out where to start her search for the boy.

‘Good evening, Lydia. Dobriy vecher.’