The French Illusion by John Grisham
Paul and Chelsea are on their honeymoon in Paris. Everything is perfect until it isn't. They find themselves drugged, separated, and taken hostage. Their families have to come up with the ransom money, but things don't go as expected. Then it turns out that they are not the first pair of American honeymooners to be kidnapped. It's a nail-biter of a tale with some compelling twists and turns.