In his mind, he’d measured every part of her. Twice, he’d passed by close enough to brush her body with his, once in the street, once in the school playground. The latter was a risk, but it had proved fruitful. In the beginning, he’d been concerned that the watching phase might be dull. How wrong he was. Familiarising himself with the lives of the ones he’d chosen had become his oxygen as the rest of his world had started to fade.

He ran appreciative fingers over the top of the dresser at his side. No dust. No sticky fingerprints from the children. Angela was all wife, mother, and homemaker. Her bedroom was the epitome of family. Photographs adorned the walls. A wedding, more than a decade ago, with a bride leaning into the arms of her groom, her dress demure, hair pinned up with just a few curls left hanging. A promise for later that night, Fergus thought.

It had taken months of patience to find a time when her husband would be away, then he’d struck gold. The man of the house had treated the children – a boy of seven and a girl of five – to a camping trip for a night, enjoying Edinburgh’s idyllic August. The husband couldn’t have realised it, but the experience would be good practice. After tonight, he would be a single parent unless he married again. Fergus couldn’t imagine why anyone would try to replace Angela. She was everything.

Each morning she walked her children to school, the boy racing ahead, sometimes on a scooter, while the girl held fast to her mother’s hand. He liked to watch them all together. Angela’s face wore an indelible smile when she was with her offspring. He’d never seen her looking tired or cross. In all the hours, all the journeys he’d witnessed, she hadn’t rolled her eyes, yawned or snapped at them. In the photos on the bedroom walls, she was not just a parent but utterly engaged in the act of parenting. He studied those pictures one last time, committing each to memory. There she was hugging her son as he clutched some sports trophy, and there she was laughing as she made cupcakes with her daughter, beaming with love. And there they were as a family on their bikes, pausing as a passerby took their photograph, defining togetherness.