Ian McEwan’s best-selling novel managed to tell a psychologically precise tale of love and betrayal, evoke a critical moment in World War II, and, most impressive, slyly question its own storytelling process. That last accomplishment lies mostly beyond the grasp of this handsome adaptation, but screenwriter Christopher Hampton (Dangerous Liaisons, The Quiet American) and director Joe Wright (Pride & Prejudice) have smartly dramatized the book’s wartime romance and tragedy. James McAvoy and Keira Knightley are excellent as the young lovers cruelly separated by a child’s lie; five years later they and the girl are swept into the vast confusion of the Allied retreat to Dunkirk, where the battlefield horrors make the characters’ guilt, anger, and heartache even more piercing. With Saoirse Ronan, Romola Garia, and Vanessa Redgrave.