Amy's always felt like something's been missing in her life. When a tragedy forces the family she works for as a nanny to retreat to a small lakeside cottage, she realises she cannot leave them now. But Amy finds something unsettling about the cottage by the lake. This is where the children's mother spent her childhood - and the place where her sister disappeared mysteriously at just seventeen. Soon Amy becomes tangled in the missing sister's story as dark truths begin rising to the surface. But can Amy unlock the secrets of the past before they repeat themselves?