Great acting can overcome a lot on the big screen, and first-time feature filmmaker William H. Macy gets a tremendous amount of mileage out of star Billy Crudup in "Rudderless."

The story -- a father (Crudup) finds his late son's musical demos and lyrics and starts learning to play them as a form of therapy -- is flawed for a lot of reasons, including a fairly simplistic understanding of the way we cope with tragedy.

There are entire characters played by big names -- Selena Gomez! Laurence Fishburne! -- that add nothing to the movie and scenes that are clearly Hollywood constructs.

But Crudup, always a first-rate and underrated performer, pours such strong and vivid emotion into the part, filling the songs with such an authentic underpinning of sadness, that the initial skepticism fades away.

Macy shares his conviction and directs with a commitment to naturalism at the expense of schmaltz.

The picture is performance-driven, without a wandering eye, to the extent that you can't help but feel moved every time Crudup's Sam busts out his guitar.

It's awkward at times, but the movie authentically communicates the feeling of being rudderless, of waking up one morning with everything you thought you knew suddenly snatched away.