In the books, Child deposits Reacher in different situations across the US and it's up to Reacher to solve what's going on. In this book, he comes across a husband whose wife has been kidnapped. Unfortunately for the guy, this isn't the first wife to whom this has happened, and as a result, as much to satisfy his curiosity as anything else, Reacher decides to find out what on Earth is going on.
It wasn't a bad book, but I've read a number of his books now and they're starting to feel a little samey. If you want that, you will probably like this book. If you don't, you'd probably do better to look elsewhere.