I always enjoy reading any book by Mary Higgins Clark. They usually follow a formula, but this one is much more intricate and suspenseful than her usual, and is the best that I have read.
Twin girls, Kelly and Kathy, are kidnapped for ransom at the beginning of the story. The money is paid, but the handover goes wrong and only Kelly is returned. Initially, it seems that Kathy has perished, but the conviction of her surviving twin convinces the parents that she is still alive. Evidence mounts, but the police are frustrated at every turn. The tension mounts as the race to find the little girl alive builds and the kidnappers become desperate.
This is a great read. It only took me a day to get through, as I couldn't put it down. Just the sort of book that you would want to chuck into your holiday suitcase!