Don’t step on the cracks - everyone knew the sense of that. One of the first things you learned as a child. But too many people forgot. Or didn’t care. Graham Smith cared. He knew that paving stones set the cadence of a street; that cracks regulated the stride length and set the resonance that kept everything stable and harmonious. Step on the cracks and the street slipped out of kilter. Imperceptibly at first. Minute changes around the edges, a new person living at number thirty-three, a strange car outside number five. Step on the cracks too often and … well, anything could happen. He’d seen houses turned into blocks of flats overnight. Parades of shops come and go. Terraces demolished, office blocks erected. All overnight when no one was looking.

The world was a far more fragile place than people realised. And every now and then a thread would work loose and something or someone would unravel.

A cloud of diesel smoke spilled out from a bus revving away from its stop. Graham stepped diagonally to avoid it, stretching three pavers over. A few steps more and he had to change lanes again, the pavement filling with commuters and tourists. He sidestepped, jumped and picked his way through the crowd. One eye on his feet and one a few paving stones ahead, searching out the next obstacle.

Which was when he saw her.

She was walking in front of him - four paving stones ahead. Four paving stones exactly, her feet studiously avoiding the cracks, just like Graham. Except that she didn’t have to dart back and forth to avoid the other pedestrians - they moved aside for her. He watched, fascinated, as a group of men split apart to let her pass, turning as they did so, their eyes scanning every inch of her, their attention wandering so much that Graham had to side-step quickly to avoid a collision.

The young woman walked on, indifferent, not looking left nor right.

Graham was fascinated. She flowed along the road, cat-like, not walking so much as dancing with the street, her feet matching perfectly the rhythm of the pavement.

Who was she?

And why hadn’t he seen her before? He walked this road every day, always at the same time. Was she a tourist? He could see no telltale sign. No camera, no map, not even a bag. Her hands swung loose by her side. Elegant hands, long and slim, like her. Everything about her resonated elegance … except … except now that he looked closer he could see that her clothes were dirty - her short brown dress looked like it had been slept in for weeks. Or was that the fashion these days? And her hair was badly dyed, a metallic red streaked with black … or was that dirt?

He followed her, couldn’t take his eyes off her, as she cut a swathe through the packed pavement. He watched her from her long, bare legs to her streaky, tousled top. She was like a sinuous metronome, clicking out an unchanging beat, looking straight ahead and not deviating an inch.

Something else caught his eye. What was that above her right ankle? A bruise? No, a tattoo. Something in blue. He quickened his pace, he had to know everything about this girl. He closed the distance between them to three paving slabs, two. He could almost make it out. A bird? Yes, a bird. A tattoo of a blue bird.

He was so engrossed he almost missed his tube station. The entrance loomed on his right like a deep, dark tunnel. The girl walked on. Graham hovered by the entrance, hoping she’d stop or turn.

She didn’t.

He had a choice. To take the tube like every other day … or follow the girl. Curiosity begged him to follow, instinct said no - he had a routine, routines had to be followed, not girls.

He looked one way and then the other. He couldn’t decide. He watched her bobbing head disappearing into the crowd, he peered into the shadow of the foyer; the turnstiles, the ticket machines. He looked back.

She’d gone.

* * *