French actress Audrey Tautou and director Jean-Pierre Jeunet, who scored in the U.S. with the puckish Amelie (2001), return with this powerful but busy adaptation of Sebastien Japrisot’s fascinating antiwar novel Un long dimanche de fiancailles. After World War I a polio-stricken young Frenchwoman (Tautou) learns that her lover (Gaspard Ulliel), reported as killed in action, has actually been marched to the front lines and tossed into no-man’s-land after being court-martialed for self-mutilation. Her search for him leads her into a thicket of backstories that leave little room for Jeunet’s whimsical humor and bizarre spectacle. The scenes of trench warfare are grim and graphic, and although Jeunet rarely allows the tempo to slow, there’s a fine sequence about another soldier (Jerome Kircher) having an affair with a friend’s wife (Jodie Foster). In French with subtitles. R, 135 min.