Ben Affleck's directorial debut is a pulpy mess of drug dealers, corrupt cops and dark bars full of daytime drinkers. But it's from the sharp pen of Dennis Lehane (Mystic River), the gritty fiction writer who documents Boston's grubbier streets. A little girl has been kidnapped, and her distraught aunt hires a local investigator (Casey Affleck). He butts heads with the feckless, drug-addled mom (Amy Ryan), police and criminals, and eventually his own moral code. While old pros such as Morgan Freeman and Ed Harris, on board as cops, easily elevate the cheesy dialogue and improbable events, Casey Affleck is too lightweight to give his streetwise Southie detective the needed gravitas. Ben Affleck moves the story, with its myriad twists, briskly, exhibiting little stylistic flair but for an overly studied snapshotting of Boston's natives, who look nothing like the Hollywood actors and all the more real for it. Starts Fri., Oct. 19.