June 1914 and a young woman – Clara Waterfield – is summoned to a large stone house in Gloucestershire. Her task: to fill a greenhouse with exotic plants from Kew Gardens, to create a private paradise for the owner of Shadowbrook. Yet, on arrival, Clara hears rumours: something is wrong with this quiet, wisteria-covered house. Its gardens are filled with foxgloves, hydrangea and roses; it has lily-ponds, a croquet lawn – and the marvellous new glasshouse awaits her. But the house itself feels unloved. Its rooms are shuttered, or empty. The owner is mostly absent; the housekeeper and maids seem afraid. And soon, Clara understands their fear: for something – or someone – is walking through the house at night. In the height of summer, she finds herself drawn deeper into Shadowbrook’s dark interior – and into the secrets that violently haunt this house.