Rhiannon had been trying to hold her breath, to stop from making a sound, but it was too hard for her – she took a long rasping gasp of air which rattled in her throat and Rachel’s torch beam swivelled round.

She came back down the stairs.

‘Who’s that I can hear?’ she said softly. ‘Is that you, kids? Are you there? Don’t be scared, it’s only me. It’s Rachel. I know you must be terrified as anything, all alone up here in the dark. Don’t worry, I’ll look after you.’

As she spoke she reappeared at the bottom of the stairs and edged closer to the pile of rubbish, her voice soft and reassuring, like someone talking to a kitten or a frightened bird that had got into the house.

Now her torch beam fell on the three of them and she smiled, tilting her head on one side.

‘There you are, my lambs,’ she cooed. ‘Don’t be frightened, now. Just look at you. You shouldn’t be out, should you?’

Sam could feel Rhiannon next to him trembling, and he could hear her breath scraping at her lungs. He gripped his butterfly pin tight.

‘Come on. Come to Mummy. I’ll look after you. Haven’t we kept you warm and well fed? Hmm? Haven’t we kept you safe from harm, kept the bad ones away? Hmm? You don’t want to go out there into the big world, now, do you? Whatever would you do? All those crazies out there. You’re much safer with Rachel and Nick, now, aren’t you?’

She got herself into a position that blocked their escape, then straightened up and bellowed at the top of her voice.

‘Ni-ick! I found ’em! They’re up here, love!’

‘Get her!’ shouted Sam, and he charged at her, butting her in the stomach with his head. She grunted and staggered back, but she was strong and Sam was only small. It reminded him of play fights with his dad. When his dad had pretended to be beaten, to be hurt, when Sam knew all along he could have picked him up and tossed him across the room.

‘Now, now,’ said Rachel, holding her temper in. ‘That’s enough of that.’ She cuffed Sam to the floor and he went down hard. But now The Kid was up and out, beating Rachel with his fists. Even Rhiannon joined in. They had all seen the meat wagon. They knew what Rachel was capable of. Between the three of them they tripped her and sent her tumbling to the ground. Sam lunged at her with the pin, but only managed to scratch her neck.

‘Where did you get that?’ Rachel roared, finally letting her anger show as she struggled back on to her feet. ‘Give that back!’

‘It’s mine,’ said Sam. ‘You should never have taken it.’

‘Give it me!’ Rachel snapped and as she made a snatch for it, Sam stabbed it into the palm of her hand. She shrieked and jerked her hand back. Almost immediately she batted him to the ground again, using the torch that she was holding in her other hand, smashing the bulb. She tried to stamp on Sam but he rolled out of the way and jabbed the pin into her leg. Her shriek this time was terrible. Loud and piercing, it echoed off the tiles. Sam scrambled up, grabbed Rhiannon and The Kid and they started up the escalator.

It was agony for Rhiannon and halfway up Sam knew they were never going to make it to the top. He was just about to say something to The Kid when there came an almighty bang and a flash and Rhiannon screamed.

The three of them stumbled and fell over in shock. Sam was stunned, the noise and the light had completely disorientated him. It was a few seconds before he realized he was unhurt, but Rhiannon was crying. She was three steps below him. He sat up and put his hand out to her. Her top was wet. He could see it stained black in the dim light. She was bleeding. Some of the shot from the cartridge had hit her.

It was clear she wasn’t going to go any further.

‘Go on,’ she croaked. ‘You’ll never make it with me.’

‘No,’ said Sam, but then Nick’s voice rang out in the half-light.

‘Don’t move, none of you, I’ll aim the next shot straight at you.’

‘Keep down,’ said The Kid, ‘and run like mad. He can’t shoot and point his torch at the same time.’

‘We can’t leave Rhiannon,’ Sam wailed.

‘Just go!’ said Rhiannon.

Sam didn’t know what to do but The Kid decided for him – he pulled Sam up by his shirt and the two of them darted up the stairs.

Nick was running up after them, but when he got to Rhiannon she threw her arms around his knees and they went crashing down to the bottom. It was all the two boys needed to get away.

They were in the ticket hall at last, a pale light showing them the way out to street level. There were shouts and screams behind them. Sam tried not to imagine what was happening, but he silently thanked Rhiannon. He would owe her for the rest of his life.

They vaulted the ticket gates and headed for the stairs.

They ran up three steps at a time.

The daylight hit Sam like a blow. He was blinded. He staggered along, shielding his eyes from the glare. It was physically painful and he had an instant headache. He was vaguely aware of a church, and tall old buildings.

He felt The Kid grab him.

‘Move it, slowpoke,’ he said. Sam squinted at him – The Kid had produced a pair of sunglasses from somewhere, a big pink pair in the shape of love hearts. Sam resisted the urge to laugh. It was The Kid who should be laughing; at least he could see what he was doing. He dragged Sam down the wet pavement. Sam could just make out, through the narrowed slits of his eyelids, where he was. This was the City of London – where old and new London butted up against each other, modern skyscrapers shouldering up through Victorian buildings on a higgledy-piggledy medieval street layout.

‘We need to hurry, dog,’ said The Kid.

Sam stumbled on, feeling The Kid tug him across the road. They came on to a paved area in front of a massive building that looked like a Greek temple. Sam’s eyes were getting a little better. They weren’t hurting so much. He looked up at the statue of a man on a horse. Then something jerked him back, and he was thrown against a wooden bench.

It was Nick.

‘I’m going to slaughter you, little pigs,’ he snarled. His dreadlocks were flapping around his head like the rays of the sun in a child’s drawing. His face, though, was twisted into a picture of rage. There was no sign of Rachel.

He held his shotgun in one hand, but, before he could bring it round on Sam, The Kid threw himself at his arm, knocking it sideways and smashing the gun into the base of the statue. The gun exploded in Nick’s hand and he dropped it, the barrel bent out of shape.

Nick didn’t waste any time and pulled a knife out from inside his coat. He glanced at The Kid. He’d fallen heavily, the gun going off very close to his face. He looked stunned. Winded.

Nick turned his attention back to Sam, who was struggling to open his eyes properly, squinting in the bright light. He saw that Nick was having trouble, too, his eyes were red and tears streamed down his face. He wiped them away and blinked at Sam, raising his knife. It was old and well used, with a wide, curved blade, worn thin from constant sharpening. He took a swipe at Sam, who ducked. He felt the knife swish across the back of his head, ruffling his hair. Nick immediately brought the knife back again and as Sam dodged to the side he felt a sting in the side of his neck. He backed away, down some steps, towards the road. He splashed through a puddle. It had been raining. He realized that the sun wasn’t even out. Though the clouds were beginning to break up in the sky.

He was breathing fast. He knew he couldn’t keep this up for long. Nick was too big, too fit. Sam was just a kid.

‘Hold still, you little pig,’ Nick hissed. ‘I’ll make it quick and painless for you. If you muck me about, though, I’ll string you upside down and bleed you slowly, just you see that I do. You’ll feel every minute of it. I promise you that. Now, hold still.’

‘Go to hell,’ Sam shouted, his voice a hoarse croak.