Fiction by Linwood Barclay.
Now THIS was a good thriller! I read it in one day.
I found it in a list of "favorite page-turning thrillers" written by the author of What She Knew, and it did not disappoint me.
The premise: A fourteen-year-old girl wakes up one morning and her parents and older brother have vanished without a trace. They never come back. But where did they go?
Read and find out!