The MacDonald’s by Kings Cross Station was a narrow, L-shaped space, wrapped around the corner of a building. It was a little past one by the time she got there, and the place was packed with tourists, teens, clean cut suits and yellow jacketed workmen. She slipped into the crowd and stayed quiet.

As the queue moved forward she was jostled and elbowed, squeezed between the taller men and women around her. She caught glimpses of wrinkled noses and disgusted or pitying glances. She mumbled her order to the boy behind the counter, trying not to meet his eyes, and a minute later she was squeezing through the crowded doorway with a greasy paper bag clutched to her chest.

It was hard to keep herself from cramming whole handfuls of food into her mouth right there and then. She forced herself to be patient, tucking the paper bag away in her backpack. Better to find somewhere quiet, somewhere safe. From across the street she caught a heavyset man staring at her. He was leaning against the wall with his hands thrust deep into the pockets of a brown leather jacket. By his heels sat a large brown mastiff, rippling with muscle under mangy fur. Just like his dog, the man had an ugly look about him, his shaved scalp revealing a long and jagged scar. She shivered, and chose a different way.

She kept moving, following weaving paths across the streets and buildings, moving up high when she could. The rain was still coming down heavily, soaking through her jacket and into her backpack. The craving for food was made worse by having it so close, growing damp in the pouring rain as she ran. Finally she arrived at a familiar back-street between an office building and a hair salon, with a wooden fence across one end. Some empty rubbish bins made an easy step up to the top of the fence, and from there she could swing across to the sill of a bricked up window at the back of the salon. Holes in the crumbling brickwork formed hand and foot holds, until she could grip the edge of the sloped roof and pull herself up. Then it was just a matter of bracing herself on the sharply angled black slates and kicking off across the gap to land on the roof of the office building.

She almost missed the jump. The worn down soles of her trainers, all the grip long since gone from the rubber, skidded on the soaking wet slates. She tumbled, flailing, and her fingers barely snagged the edge of the office roof. Gripping tight, she tucked her legs up in front of herself and only just managed to soak up the impact with the wall. For a moment she just held on, the stone parapet tearing at her fingers. She felt paralysed, unable to make any movement for fear of falling, but sure that any moment now her grip would fail. At the last moment she kicked out with all the strength her legs had, hauling herself upwards, oblivious to the pain in her hands. Muscles burning, she dragged her body over the edge of the rooftop and collapsed onto the other side.

She stared at the sky, drawing ragged breaths, feeling every muscle burn with the strain. The cold air tore at her lungs as the rain washed over her face. She flexed her fingers experimentally and tried to move her arms a little. Blinking, she shook the water from her eyes. The rain was finally easing off.

She rolled over onto her knees and stood up. It had been a while since she'd missed that jump. She’d been so distracted by the hunger that she hadn’t even considered the wet slates. Feeling like kicking herself, she trudged across the rooftop to a familiar hidey-hole beneath a ventilation duct. The duct was warm, and tucked away beneath it she felt her clothes begin to dry a little. She undid the hood of her jacket and let her hair spill out.

Unzipping her backpack, she pulled out the now sodden paper bag. Her burger was damp, the bread all mushy on one side, but she hardly cared. She forced down mouthful after mouthful, any other thought obliterated by the simple ecstasy of food. She devoured a box of fries just as quickly, washing it all down with sips of water from a plastic bottle. Finally she eyed the second burger she'd bought. Fighting temptation, she tucked it away for later.

Delving into her pack once more, she produced a bundle of plastic bags which she carefully unwrapped. Inside was a large pad of stiff white paper, somewhat wrinkled with damp despite the plastic, and a small bundle of pencils. Resting the pad on one knee, she picked out a soft pencil and began to sketch. Bold lines swept across the page, picking out the rough shape of the river, bulbous and grey, the North Bank skyline rising like crooked teeth above it.

Hours passed as she lost herself in the movements of the pencil on the paper. When the sun finally showed itself from behind the thick blanket of cloud it was long past noon. Her legs were numb, pins and needles sparking as she moved them for the first time in hours.

She looked down at the page again, seeing the whole drawing for the first time. She had half a mind just to scrap it, but instead she closed the sketchbook and carefully wrapped it up again. The battered pages were filled with abandoned pieces, never quite as good as she wished they could be. In the plastic bag lay another four sketchbooks, their pages all filled with the results of an endless succession of empty days. They were warped by the damp and mostly falling apart, but she kept them all the same.

She crawled out from the space under the vent and stood up to stretch her sore muscles. As she stood, her eyes took in the rooftop and she stopped dead, clutching her bag to her chest in alarm.

The boy was perched on the far edge of the roof, crouched low, his feet balanced on the parapet. There were holes in his jeans and he wore boots that must have come from an army surplus store. The tails of a long black coat were bunched around his heels. The way he perched, he looked a little like a bird.

His look of astonishment mirrored her own. For a moment they both stared at each other, not moving, not breathing. Then, unable to help herself, she glanced away. It was only for an instant, her eyes searching for a way down, wanting to be sure of an escape. When she looked back to the boy, her breath caught in her throat. He had vanished. It had only been an instant that she had looked away, but already he was gone. She heard a flutter of wings. Startled pigeons taking flight.

She ran to the edge of the roof and looked down, sure he must have jumped off. It was three stories, a hard drop even with a hang from the edge; she'd done it herself, once or twice, but it had frightened the life out of her every time.

The street was empty. There was no sign of him at all.