April brings spring surging with it, giving rise, among many in the village, to a comforting illusion that all is somehow still right with the world, and that nothing will ever change.

In the ancient Welm Valley, something is shifting: the river is behaving oddly, while the arrival of spring, with its familiar rhythms, is shadowed by an undercurrent of unease.

A woman falls while out walking and hopes to be found before nightfall; a builder experiences sudden, overwhelming vertigo on a farmhouse roof; across the village, people are plagued by the same vast, strange dream. And alone in the converted priory, overlooking watermeadows unchanged for centuries, Clare Grey receives devastating news which will force her to reconsider her family's past and the fresh weight of her solitary existence.