She walked swiftly upstream along the path, hopping over tree roots and rocks, searching left and right. She swept the thickets with her eyes, alert for any trace of the lime-green car seat covers clipped to the stroller. In the woods, there seemed to be flashes of lime-green everywhere, so that her eyes kept alighting on patches of new leaves, bright bushes, thinking, there it is, and realising a second later that she was mistaken. Even an old plastic bag caught her attention, before she thought, if it were that easy, they’d have been found already—after all, she was going over old ground, places that had already been searched before she arrived. Every so often she stopped dead, listened for the cries of babies, but heard only birdsong, and her own slightly quickened breathing.

The light dimmed rapidly under the canopy as the clouds knitted together above it. She pressed on, nodding at three uniformed officers waist-deep in undergrowth, all of them scouring the ground for evidence of the abduction, for anything that might help the search.

She passed a wide, deep section of river where the path was low, only just above the level of the water. The edge here curved around, creating a little shore. It would have been easy to push a stroller in at this point, but there were dozens of places up and down the river that were similar. She had a quick search for tyre tracks, saw none. Up ahead, the tunnel created by the river and the woods turned a corner that she couldn’t see around. Just a bit further, she thought, then I’ll go back the other way and get a good look at the millpond myself.

She heard the rain before she felt it. Loud and heavy as stones falling on the leaves above. I’ll just go as far as the corner, she thought, but then drops of water big enough to hurt began to land on her arms and head, soaking her in moments. She jogged to the bend in the river; she’d come this far after all.

And there they were.

A female dressed in dark clothing was knee-deep in water, struggling with the double stroller, which was at an angle, tipping into the sluggish murk. The lower seat was almost underwater. Any further in and it would fill up.

Harper sprinted towards the scene, the woman, the water all around them full of tiny explosions of raindrops battering down, the noise of it almost but not quite drowning out Harper’s cry of “Stop, police,” but the figure turned, saw her, shouted out and let go of the stroller. She turned her back on the pushchair, the lightning flashed, and she pulled her sodden form onto the bank. She tried to run, but even before the thunder could answer, she flew straight into a uniformed officer who’d come from further upriver.