Plus, "Gone Baby Gone" is set in Boston, familiar ground for Casey and Ben, and also Dennis Lehane, from whose novel this dark, plot-heavy movie is adapted (it's as dense and depressing and pedophile-strewn as "Mystic River," another Lehane novel that reached the screen).
Casey plays Patrick Kenzie, a private detective hired by the uncle of a missing and criminally neglected child. Kenzie gets the job because he's a neighborhood guy who knows all the drunks and dealers and dopers, and might be able to cover ground off-limits to the cops.
The lead detective (Ed Harris) naturally resents this, and so does the chief of police (Morgan Freeman), a man who's devoted his professional life to protecting children.
This is a great cast (there's Michelle Monaghan as Kenzie's girlfriend), and the movie has additional strengths. Director Affleck captures the flavor of the neighborhood and its people (not always flatteringly), and has an obvious feel for the environment that Lehane is writing about.
He handles a complex story with skill, paces it well, and his characters have sharp definition. He's good, for instance, at showing how Kenzie's competence wins over the resentful police.
Whether Casey Affleck wins the confidence of the viewer is another issue. There's a scene that calls for the elfin Affleck to walk into a saloon and rough up some gigantic, scary goons, and it frankly doesn't work (there is a reason he did so well in "James" as a pip-squeak).
If Casey's too small for his role, the great Morgan Freeman may be too big for his. Freeman carries considerable weight as an actor, and you expect his character's influence on a story to be considerable.
If you're an active viewer, and you account for this influence, it's possible to deduce how this convoluted story is going to play out, taking the oomph out of what should be a knockout ending. *
Produced by Alan Ladd Jr., Dan Rissner and Sean Bailey, directed by Ben Affleck, written by Ben Affleck and Aaron Stockard, music by Harry Gregson Williams, distributed by Miramax.