Thirty years ago, the official verdict was that thirteen-year-old Zoe Gray accidentally drowned. But when her sister Claire inherits the family home, she discovers her sister's secret diary, which tells a very different story. Claire discovers that four schoolgirls in Zoe's class were guilty of appalling acts of bullying that ultimately led Zoe to take her own life. She vows to avenge her sister by finding and punishing the women responsible. The four schoolgirls are now in their early forties, and all are leading wealthy and privileged lives, where golf and shopping enable them to keep their demons at bay. The tragedy of Zoe's death has defined their own lives, and kept them close to each other, united in guilt that is never spoken about. But suddenly, out of the blue, someone is threatening to strip away the safe veneer of respectability they've built around themselves. They all have so much to lose. Yet as the story unfolds, even more astonishing are the secrets they've never shared with each other . . . As Claire starts out on her journey of revenge, she finds herself in a world where nothing is quite what it seems. Will she succeed in avenging Zoe? And are there further secrets to be uncovered?