The last goodbye / Tim Weaver.

One day ago. On the night Tom Brenner and his nine-year-old son Leo visit the Seven Peaks theme park, they head straight for the ghost house. They go in. But they don't come out. Somewhere inside the ride, impossible as it seems, the two of them simply vanish. Forty years ago. When Rebekah Murphy was three, her mother walked out of their childhood home and never returned. Nearly four decades on, Fiona Murphy is still missing. But then, out of the blue, a letter arrives in the post. It says it's from Fiona. What is the connection? Missing persons investigator David Raker is hired by Rebekah to find out if the letter is actually from Fiona - and, if it isn't, why someone would pretend to be her. But this is a mystery whose secrets were never meant to be found. And as Raker starts to connect the dots from Fiona to the Brenners, he begins to realise he can't trust anyone.