One

The event that changed all of their lives happened on a Saturday afternoon in June, just minutes after Michael Turner—­thinking the Nelsons' house was empty—­stepped through their back door. Although it was early in the month, London was blistered under a heat wave. All along South Hill Drive windows hung open, the cars parked on either side hot to the touch, their seams ticking in the sun. A morning breeze had ebbed, leaving the sycamores lining the street motionless. The oaks and beeches on the surrounding Heath were also still. The heat wave was only a week old, but already the taller grass beyond the shade of these trees was bleaching blond.

Michael had found the Nelsons' back door unlocked and ajar. Resting his forearm against its frame, he'd leant in to the gap and called out for his neighbours.

"Josh? Samantha?"

There was no reply. The house absorbed his voice without an echo. He looked down at his old pair of deck shoes, their soles thick with freshly watered soil. He'd been gardening since lunchtime and had come straight over to the Nelsons' without washing. His knees, showing under his shorts, were also smudged with dirt.

Hooking the heel of his left shoe under the toe of his right, Michael pulled it off. As he did the same with the other, he listened for signs of life inside the house. Again, there was nothing. He looked at his watch—­it was twenty past three. He had a fencing lesson on the other side of the Heath at four. It would take him at least half an hour to walk there. He went to push the door wider, but on seeing the soil on his hands, nudged it open with his elbow instead, then stepped inside.

The kitchen was cool and dark, and Michael had to pause for a moment to allow the sunlight to dissolve from his vision. Behind him his neighbours' garden sloped away between a pear tree and a shrunken herbaceous border. The parched lawn tapered to a wooden fence shot through with reeds. Beyond this fence a weeping willow bowed to one of the ponds on the Heath. In the last month these ponds had grown a skin of green duckweed, surprising in its brightness. Just a few minutes earlier, while resting on his heels, Michael had watched a coot as she'd cut her way through it on the far side, her nun's head pumping her forward, a cover of chicks crisscrossing over her wake.

Standing in the kitchen, Michael listened once more. He'd never known Josh and Samantha to leave their house unlocked and not be home. He knew Samantha was away with her sister, Martha, for the weekend. But Josh and the girls, he'd thought, had stayed. The house, though, was silent. The only sounds Michael could hear were from the Heath at his back: a dog barking, the chatter of distant picnics, the splash of a diver from the swimming pond beyond the walkway. Closer, in a nearby garden, he heard a sprinkler begin chopping at the afternoon. Such was the stillness of the house that from where he stood in the kitchen these sounds already had the texture of memory, as if he'd crossed a threshold in time, not of a home.

Perhaps Josh had left a note? Michael went to the fridge to look. It was a broad-­shouldered American model in brushed steel, an icemaker embedded in its door. A desk's worth of papers jostled for position across its surface, pinned under a collection of Rothko fridge magnets. Michael scanned the takeaway menus, shopping lists, school notes, but none of them gave any clue as to where Josh might be. He turned from the fridge and looked around the rest of the room, hoping to find something that might explain why the back door was open but no one at home.

Like the rest of their house, Samantha and Josh's kitchen was solid and generous. At its centre the slatted shadow of a venetian blind fell across an island work surface. Around this were an oven, two hobs and a chef's array of utensils. On the other side of a breakfast bar, potted plants fringed a sagging sofa and two armchairs in the conservatory, ochre blinds drawn over its glass. Back within the kitchen itself, an oval dining table occupied the far end of the room, and there, hanging above it, were the Nelsons.

Excerpted from I Saw a Man by Owen Sheers. Copyright © 2015 by Owen Sheers. Excerpted by permission of Nan A. Talese. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.