Have her! Natasha shouted, but it came out as an animal roar, nothing intelligible in that violent outburst. And there that brief period of coherence ended. Natasha screeched, power thudding through her child's body and firing every nerve end, rage pumping her blood and spasming in her muscles, pain singing from every bone that sought to distort and be something it could not. Her jaws opened wider, her arms grew longer, fingers were pincers, nails were claws, and her teeth throbbed in her gums at the thought of fresh flesh ready to part beneath them. She took a bite out of the woman's face and then threw her at the man. As he caught the body and stumbled back, Natasha's little brother fell on him from above and ripped out his throat.

There were still some people left alive, a core of defenders that had retreated to a far corner of the basement thinking that their guns would protect them there. Natasha and her family ducked down behind tables and furniture, slinking through the rooms, smashing through glass partitions where they had not already been destroyed by gunfire. Where they found someone living—a man hiding in a cupboard, stinking of piss and fear; a woman taking huge snorts of white powder from a shattered glass vial—they slaughtered them, relishing the splitting of their bodies, spreading insides across the tiled floor. Where they found a dead body they slashed at it on their way past, or perhaps paused to swallow a ruptured eyeball or take a mouthful of exposed breast. It took only a minute to come together, Natasha and her brother, their father and mother, all of them coated in blood, their own, and others', mad, raging, berserk. Her brother spat gobbets of meat from his mouth and slashed at metal furniture, his nails squealing across its surface. He was still young, still learning to direct this rage.

They did not speak, because in this state such communication was all but impossible. Tom, part of Natasha through her memory and yet still an independent observer, realised that everything for the berserkers was instinct. Like a pride of lions on the hunt, or a flock of birds weaving back and forth across the sky, they knew what to do and when. Natasha's father growled and broke left, her mother moved to the right, and Natasha and her little brother waited for a few seconds, preparing to leap over the bank of metal cabinets they hunkered behind.

The humans gathered in the corner of the room were shouting and screaming and crying, letting off bursts of gunfire at shadows thrown by flickering lights. Natasha could smell their fear, and it was good. She could also sense the meat of them, their pumping hearts, their pulsing blood, the flesh of their thighs and the tender taste of their throats. She glanced sideways at her brother and tried to smile, but her tooth-filled mouth would not allow her. He tried to smile back.

Their parents roared at exactly the same moment, launching their attack, diving into the humans unfortunate enough to be on the outside of the group. Guns exploded, bullets whined and whistled around the basement, thudding into walls and ricocheting from furniture.

Natasha and her brother leaped onto the metal cabinets and looked down at the violence below.

There were maybe ten people left alive. Their father was to the left, standing on his hind legs disemboweling a man while a woman fired at him again and again. His body danced and jigged, feet kicking him from the wall, jumping from the floor, dodging bullets as his face and hands remained working on the man. He turned suddenly on the shooter, snatched her gun and buried it barrel-first into her face. One of his claws caught the trigger and the back of the woman's head erupted into the air.

To the right their mother was a blur of thrashing limbs and snapping teeth. A man fell before her, screaming as she pulled herself up his body and opened it every inch of the way.

Someone shouted, someone else pointed, and bullets screamed at Natasha. The memory blurred as she danced left and right, jumped and powered down from the ceiling, bounced from the floor. The whistle of bullets passed close by, and their paths sometimes left hot streaks across her skin. And sometimes, they struck her. Peter whined behind her as a bullet found home. He fell to the floor beside her, growled, and they leapt together. Both of them found meat.

The lights went out as one last desperate burst of gunfire found a switching panel. The stench of an electrical fire added to the odour of opened bodies. But the humans were all dead or dying and already the rage was subsiding. For the berserkers, there were wounds to heal and expended energy to replace.

Natasha and her family settled down to feed.

Do you see? Natasha asked. Do you see now what they made us do? Her voice was weak and tired, barely there at all. Tom could feel her inside his head but there was not the sense of invasion there had been before. He almost had to search to hear her voice.

"I saw," he said. "But I don't understand."

I'm tired, she said. So tired. I haven't fed for so long, Daddy. I need to go away for a while.

"Wait!" Tom said, "we have to decide where to go, what to do."

Yes, we have to leave, she said, to leave, he's coming, Mister Wolf is coming … but I'm really only a little girl. She faded away at last. Tom could not be certain what he heard in those final few words: vulnerability, or hopelessness.

He sat there in the morning sun, the unearthed girl in his lap, cows staring over the gate at him with disinterest. A sparrow hawk hovered high overhead, stalking something a couple of fields away. Bees buzzed the hedge, and a tiny wren darted in and out of the undergrowth, picking insects from leaves, wagging its tail to gain balance each time it landed. Tom wished that he could find his balance so easily.

He loved the countryside, and right now it was shielding what had happened from the eyes of the world. His battered car, his dead wife … he could see her feet and lower legs through the open back door. Jo, he thought, but suddenly the idea of that body being his wife was alien and distant. She was somewhere else now.

Tom stood, carried Natasha and her chains to the car and set her down on the bonnet. It was only as he let go that he realised how easily he had moved. He paused, standing still, trying his best to discern exactly what had changed. Eyes closed, he heard so much more. Hands over his ears, he saw more. His head no longer hurt, and the aches and pains in his limbs had faded. He thought back to the memories Natasha had shared with him … but it was more than sharing. He had seen what had happened in that house. She had not told him about it, nor explained it, she had shown him. In the same way that she came into his mind to talk to him, so she had invited him into her mind to know more of her.

And what did I find? he thought. That she's a monster? Some sort of wild animal, immune to bullets and knives, impossible to kill, a killer herself? But he shook his head and looked down at the strange body on the car bonnet. She was more than an animal, and more than simply a killer. She was more than human, not less. She was, as she had told him, a berserker.

Do you see what they made us do? She had whispered before slipping away into a deep sleep. They kept us hungry.

Tom had to leave. He felt refreshed and strong and ready to move on, and though the grief over Jo sat heavy on his shoulders, there was still a numbness that held back the tears. He looked through the shattered windshield at his dead wife on the backseat, and it was not her. That is not Jo! There lay the body he had touched and loved for over thirty years, and yet she was not there. She's dead, he thought, dead and gone forever and I'll never see her again, never smell her or taste her or talk with her again for all eternity. But though the rage and grief were there, something kept their full effect at bay, a numbness that promised worse to come.