We should have protected her… They'd left their daughter with us, their only child, and we hadn't protected her. That was all they would see when they looked at us-that we had failed them. I count down the days until we can leave the city behind and return to the beach house. Where James and Katie can roam free over the dunes, like they did as children, and Peter will swap his 6 a.m. starts for the stacks of fluffy pancakes he lovingly serves up for our family breakfasts. These sun-drenched, golden days, just the four of us, are what I hold on to all year long. But this summer Katie's best friend will be coming with us. I tell myself the girls will have fun together, pushing aside the doubts I have about this uninvited guest. Isa. With her corn-silk hair and luminous skin, who manages to overshadow my daughter at every turn. Who has been dumped on us by her own parents, too caught up in their petty dramas to see what is right in front of them. Because I can see it. There is something dangerous about Isa. Something more than a carefree girl, testing boundaries as she approaches adulthood. She threatens to cast storm clouds across my beach house days. I feel as powerless to stop her as I would in the face of a hurricane. By the end of the summer, Isa will be dead. And I will have to face her mother. I don't know if I will be able to find the words. How can I begin to explain that she never really knew her daughter at all? A gripping story of the darkness than lurks beneath the surface of the most picture-perfect lives and the lengths we will go to protect the ones we love. Fans of Big Little Lies, Kerry Fisher and Diane Chamberlain will be held totally in thrall by this emotional, twisty read.