Midnight Line by Lee Child

In Midnight Line, Jack Reacher, ex-military man and now inveterate wanderer, comes across a West Point ring in a small town pawnshop. Knowing how hard 4 years at West Point can be, he is determined to find the owner and return the ring. All he has to go on is the small size--indicating it belonged to a woman--and the initials inscribed inside the ring. His journey takes him to the middle of nowhere out West, where he teams up with an ex-FBI guy (now PI) as well as the PI's client, whose sister may be the owner of the ring and who has gone off the grid. A small town cop and a DEA agent also get entwined in Reacher's latest adventure. Good story. And I think there's a new Reacher novel coming out later this year, so we can see where the road takes him next.