In the days following September 11, 2001, U.S. Army Special Forces under Capt. Mitch Nelson (Chris Hemsworth) deploys to Afghanistan, riding horseback into battle with the Taliban. Doug Stanton’s nonfiction book The Horse Soldiers, adapted by Ted Tally and Peter Craig and directed by Nicolai Fuglsig, makes an enjoyable old-fashioned war movie, spruced up with the kind of graphic combat action that couldn’t be done back in the day. Hemsworth, who grows in stature with every movie, makes a real-life action hero even more stalwart than his comic-book Thor, ably supported by Michael Shannon, Michael Peña and (as their Afghan ally) a scene-stealing Navid Negahban. The movie avoids ruminating on America’s Afghan policy, and ends before things get complicated, making it an upbeat movie about a downbeat war. J.L.