By the winner of the Betty Trask Prize an atmospheric and powerfully menacing story about family, secrets and violence

'Richly unsettling ... A masterclass in apprehension' Daily Mail
'Unsettling and seductive' Irish Times
'A masterful portrait of the fractious, shimmering webs underneath our not-so ordinary lives' Sophie Mackintosh
'Complex, chilling, masterful' Financial Times
'This is a novel that gets right under your skin' Ella Frears
John and Liz have left the city behind to move to a remote house on the shores of the lake. Though the house is barely unpacked, Liz's sister, with her children and her husband, have come to visit for the August bank holiday weekend.
Over the course of a hot, slow weekend, tensions simmer; things go unsaid between the two couples, between the two sisters. Their time together is punctured by visits from Jim, the solitary local warden for the area; and a group of students camping nearby draw closer and closer, finally infiltrating the house and bringing their own tensions and hierarchies with them.
As the weekend draws to a close, the landscape reveals a violence that has long lain hidden and the summer builds to its harrowing climax.
Taut and menacing, full of disquiet and tenderness, Groundwater is about the gulfs that lies between us and those we love and the miraculous ways our deepest desires and fears manifest.