Helen and Michael Pengilly are on a dream holiday in Central America with their children, Reuben and Saskia. But a sinister stranger is watching them - and on their way to the airport, a horrific accident devastates the family, leaving Saskia fighting for her life. Terrified as she recovers in hospital, Helen's memory is dragged back to a decades-old tragedy, while other pieces of the fugitive life she and Michael have lived for so long start to fall into place. A slashed car tyre. The night Helen was followed home in Kent. Silent phone calls at 3 a.m. Two bouts of severe food poisoning. To protect their family, Helen and Michael both said they would forget what happened. But there's someone who will stop at nothing to make them remember...