Honor is heading west out of London. At this time of night the traffic is light and flowing freely over the Westway and on through the outer suburbs towards the M4 and she’s thinking about how quickly the years have flown by since she first decided to quit the Welsh Marches and begin life afresh with Nevis on the canal in the eastern fringes of the capital. Was that the best decision? It seemed important, no, vital, then to leave everything behind, to be able to say goodbye to the painful memories and the dreams of revenge. Zoe’s death still felt so raw then. She would never break free, she knew, not while the man who was responsible for Zoe’s death was out in the world. Every patch of woodland reminded her of their foraging days, every passing caravan spoke of their life together, every bridge brought back agonising memories of her best friend’s death. Zoe haunted her every waking hour and came to her in her sleep. The only thing that thrived inside her during those first months was hatred. Here she was, at nineteen, with her best friend dead and Zoe’s baby to raise and no idea whether she had the strength to survive any of it. She’d lived like a zombie, warming Nevis’s bottles and changing her nappies on autopilot. Becoming the best mother she could be had taken second place to her all-consuming grief and the naked, desperate desire for revenge. And then she woke up one day and realised that love, a simple mother’s love for her daughter, had crept up on her and grown so fierce and hot that it burned out all the bad.

Nevis, you saved my life. Why have I never told you that?

The van tocks across the concrete panels of the road.

Need speak now.

Has Honor ever known Nevis need to speak before? She doesn’t think so. Nevis doesn’t like talking. She can go whole days and barely say a word. Even as a young child speaking came hard to her and as she grew older she opened her mouth less and less. Honor got the impression that she had secrets and liked to keep them. A legacy of her birth mother. By the time Nevis reached adolescence she barely spoke unless there was some information to impart. With Nevis it was more than the casual teenaged sullenness for by then she had discovered her own true language. Mathematics. For Nevis the turns of algebra and rhythmic shapes of geometry were more eloquent than spoken language ever could be. And so for her to need to speak now, in the middle of the night, to Honor who she hasn’t properly spoken to in months, something very important and very urgent must have happened. But what?