A secluded house. A lost notebook.

A wartime secret. 1942: Young Irish nurse Ellen arrives at May Day House, tasked with helping the men there rehabilitate.

But there’s something strange about the house, surrounded by water, on its own island in the Thames. And then there are the men: traumatised by their experiences of war, and subject to troubling methods in a desperate race to get them back to duty.

As Ellen gets drawn into the world of May Day House, she starts to realise this will be no place to hide away from her own troubles…2013: Philip and Meredith are the proud new owners of May Day House. Following a string of tragedies, the couple have moved to the area in search of a new start.

But all is not what it seems in the riverside community. As their plans for the rundown house meet resistance from the neighbours, Meredith finds herself slowly unravelling: she hears voices on the water, sees figures where there can be no one there.

When she finds an old notebook from the war, she seeks solace in the stories about the former patients of the island. But will shadows from the past threaten her future happiness – and even her life?.