As children, siblings Gareth and Helen went ignored and utterly unsupervised in their isolated English farmhouse while their mother obsessively tended to her beloved, exquisite garden. When they were little, Gareth would occupy himself by trapping insects under glass and Helen would find ways to entertain herself - but the older they grew, the more sinister their lives became, with no attentive parent to shield them from the predators of the world. Decades later, Helen is in the same crumbling house, unhappily married and looking after their bedridden mother, and Gareth finally returns home. Evidence of a long-ago crime has recently emerged, and in its wake will come a series of shattering truths . . .