Or worse.

Because when they didn’t die, when they lived on as mindless, shambling creatures with decaying bodies and a taste for fresh meat, it was much, much worse.

The kids who’d taken shelter in the Tower of London tried to forget. They tried to delete the memories of all they’d lived through, but when they slept some deep part of their brains kept on reminding them, and suddenly they were back there, reliving it as a loved one got taken by the disease, or as friends were attacked by the hungry things that had once been human. Suddenly they were hiding again from their own families, trying to get away as a mother or a father reached out for them with rotting fingers …

They would talk and struggle in their sleep. They would cry out. There would be screams in the night. Some would sleepwalk and be found in strange places spouting gibberish. More than once someone had woken to find a friend with their hands round their throat.

DogNut was no different. On the night before he was due to leave the Tower he had his old familiar nightmare once again. Why this one? This same dream, night after night? Why would his brain not leave this memory alone? He’d survived more dangerous attacks. Lost closer friends. So why, in the darkness, did the dream come creeping like some low shadow creature into his brain? So that even he, tough and wiry and street-smart and seemingly scared of nothing, would jerk awake, tangled in his bedclothes, crying like a little baby and calling out for his mum.

Every night the dream ran its course. He could never wake himself before that final terrible moment …

Maybe it was the weirdness of what had happened, the fact that he’d seen nothing quite like it before or since. The slow, disgusting, unreal nature of it. It had even felt like a dream at the time.

It had happened soon after he’d arrived at the Tower, when they were all still learning about their surroundings, before they’d turned the business district to the north and west into a forbidden zone. All the big office blocks and skyscrapers were here, even though it was the most ancient part of the city, founded by the Romans some two thousand years ago. It was an area where far-out, modern, hi-tech buildings of glass and steel rubbed up against medieval churches and solid, stone-clad eighteenth- and nineteenth-century buildings decorated with pillars and columns and statues.

This part of London seemed to contain a special sickness all of its own.

But all those months ago they hadn’t realized …

In his dream DogNut is back there, out on patrol with his friends Ed and Kyle and a boy called Leo. Leo is a chatty kid who’s pretty tough, but also more than a little clumsy. So, although he loves fighting and is always the first to volunteer to go out hunting for food and supplies, he is as much of a danger to his own side in a fight as he is to any attacking sickos. DogNut is always nervous going on patrol with him – he doesn’t pay attention and is noisy and too sure of himself – but today a lot of the other kids are laid up with the flu and he’s the best available.

They walk along a wide street. In his dream it’s black and white, like an old film. Bank notes are blowing in the breeze like confetti. The four of them laugh and try to catch as many of them as they can, even though they are completely worthless now. They follow the trail of money and it leads them to a fancy-looking Victorian building with an imposing front that reminds DogNut of a Greek temple. It’s the money that brings them here. There’s smoke rising from the building, but the boys are curious to look inside. To find the source of the money.

The revolving doors at the entrance are locked. The window next to them, however, has been smashed, and, carefully avoiding the broken glass, they climb inside.

They are in what appears to be a posh bank of some sort. There’s a wide marble floor, with a circular pattern of tiles set into it that looks something like a compass. There are pillars and carved wood, and paintings on the walls, a couple of big dead trees in pots. At the back is a staircase leading up from the lobby, to the left an empty reception desk. There are no signs of any human activity.

Leo is keen to explore further.

He says something about looking for gold.

Notes aren’t much use, but gold will always be valuable …

They walk towards the stairs. And as they get to the middle of the tiled pattern on the floor, there is a crack and the floor begins to crumble beneath their feet. DogNut instinctively grabs on to Leo and they hold each other as the floor collapses. In the dream it happens slowly, they almost float down, but at the time they must have fallen hard and fast.

Right down to the basement.

Miraculously they are unhurt. They’ve landed on something soft. The air is filled with dust so for a few moments DogNut can’t see anything, despite the sunlight filtering down from the floor above.

Ed and Kyle had been walking a little way behind them and haven’t fallen through. DogNut hears Ed calling down to him, asking if he’s all right.

DogNut shouts back that he’s fine.

We landed on something … He tries to work out what exactly the two of them are standing on … or rather in. He’s sunk up to his waist in something warm and slimy. And it’s moving, like some giant animal.

‘What is it?’ says Leo.

‘It’s bad is what it is,’ says DogNut. ‘We got to get out of here.’

‘But what is it?’

‘I don’t want to know. I just want to get out.’

As the air clears, DogNut notices that there’s a sort of luminous glow down here. It helps him to gradually make out his surroundings.

Faces. Too many to count. Looking up at him. He’s sinking in a sea of faces. He realizes that the sticky mess he’s fallen into is people. They’re all squashed together, and it’s as if they’ve melted into one single, shapeless blob. They are stacked on top of each other. He can see more faces underneath. Bodies crushed and trampled and squashed beneath the feet of those people at the top.

They’re smartly dressed in business suits, although the suits are filthy and ragged, and some of the men and women wearing them are obviously dead. Not all, though. Hands wriggle up from the gloopy mass, fingers worm towards him, heads crane over to try to get closer, but the bodies are so tightly packed that none of them can really move.

DogNut looks around; the whole basement is crammed full of these people. How they live down here, what they eat, he has no idea. Maybe they eat whatever drops in on them. But then he sees to his horror that they are eating each other. Where they are able to they’ve clamped their mouths on to their neighbours. Over there a head has three or four other heads clustered round it, sucking and chewing. And there – two heads eating each other. He watches in appalled fascination as a mouth peels the cheek off a woman, exposing her gums. She has long since lost her teeth. The only sound is a squelching, slurping noise. There’s something cold and dead-eyed about these people, as if they didn’t care. They look like lizards.

And now DogNut realizes that they are trying to eat him too. There are three mouths sucking at his legs. He pulls one leg away and it comes free with a plopping noise. He frantically kicks and wriggles, but as one person is knocked away another fills the gap.

‘This is disgusting,’ he shouts.

‘Go up,’ says Leo. ‘We have to go up!’

The ceiling is nearer than DogNut had expected. God knows how deep this human pool is. He forces his way up, standing on shoulders, heads, jerking away from gaping mouths. Ed is leaning over the edge, his hand extended downwards. DogNut reaches up and his fingertips touch Ed’s. But then the panicking Leo pulls him back.

‘Let me go first!’ he screams, and climbs up DogNut’s body, using him as a ladder. DogNut swears but tries to help him, pushing him from below. In his panic, though, Leo slips and tumbles sideways, falling into a field of upturned baby birds’ mouths. He thrashes about and only succeeds in sinking deeper into the human bog.