I noticed that this movie was available "for free" (with Amazon Prime), Mrs. Salad was off to do her Day-of-the-Dead thing, so I watched this with my dog. Better than I expected! I read the book a year ago and still remember most of the plot details; I can report that the movie does a half-decent job of hitting most of the main plot points.
After some inadvertent heroism bringing bad guys to justice (in an unnecessarily complex way), Jack resolves to visit Susan Turner, the comely lass (Cobie Smulders, woo!) who has his previous job with the Army's MPs. As in the book, she's somewhat intrigued by the dent left in her desk during his tenure, which he made with some miscreant's head. But when he gets there, Susan's been arrested and jailed on a trumped-up charge, and her life is (obviously, to Reacher) in terrible danger.
So, as in the book, Reacher engineers a nifty jailbreak, and he and Susan are off to investigate the real villains. Complicating things somewhat is a paternity suit against Jack. So they also track down the alleged daughter, Samantha; at first glance, it's completely credible that she's an apple dropping near the Reacher family tree.
There's a cute bit of blink-and-you'll-miss-it trivia that I'll just drag in from IMDB:
Source novelist Lee Child, author of the 'Jack Reacher' novels, has a brief cameo as a TSA agent who is seemingly ambivalent to the fact that Jack (Tom Cruise) does not really match the stolen ID he is using to board the plane. This is a nod to Child's support of the "controversial" casting of the diminutive 5'7" tall Cruise as Child's 6'5 tall," 250lb weighing, and 50-inch wide-chested character of Jack Reacher. Despite a lot of fan backlash at the casting of Cruise, Lee responded: "Obviously, Tom Cruise doesn't match the physical description of Reacher in the books, but the movie is not going to match the book anyway."
Mr. Child is a good sport about this, which may be related to the suitcases full of money he gets from the filmmakers. Which is fine, and I enjoyed the movie, and I like Tom Cruise, but: really, we should be seeing Kiefer Sutherland in this role.