"THE IMPOSSIBLE," a distant cousin to "Flight," uses a disaster as the pretext for a probing insight into the responsibilities of the individual amid catastrophe.

It's based on a family who experienced the Indian Ocean tsunami that hit Thailand in 2004, fictionalized here as the story of Harry and Maria Bennett (Ewan McGregor, Naomi Watts) and their three children, spending the holidays at a beachfront Thai resort when a giant wall of water smashes into the hotel.

Director J.A. Bayona ("The Orphanage") sketches the family and its dynamics in a few deft, quick strokes, so we know them just well enough when disaster strikes. The tsunami arrives in a brief but harrowing sequence - a technical triumph, some of the best effects work we've seen since, well, "Flight." (The entire production, with throngs of extras and extensive location shooting, is a marvel.)

Bayona cuts between panoramic shots of the monster waves hitting land and close-ups of victims in the roiling water, tumbling under and above water as the current sweeps them along.

Harry and his two youngest boys disappear. Maria and her eldest son Lucas (Tom Holland) survive the initial ordeal. Lucas is ferociously protective of his wounded mother, determined to see that she survives - at the expense of other considerations. His moral triage is a little ruthless - he argues they shouldn't waste time looking for the rest of the family on the grounds that they are surely dead (the grim landscape augers for the truth of this).

On the other side is Maria, whose maternal instincts are just as fierce - she tells her son they will continues searching for the rest of the family if it is "the last thing we do."

Thus is established the movie's ethical framework - Maria, badly injured and evacuated to a hospital, using the last of her strength to insist that Lucas dedicate himself to finding his brothers and father, and, failing that, to helping others.

There's an effective sequence of Lucas, his moral sophistication growing, interviewing survivors at the hospital (a patchwork of nationalities and languages), trying to match the missing with those searching for them.

The movie has eloquently made its points and could have ended there, but is bound by convention to resolve the story of the Bennett family - the simple plot mechanics of whether and how the storm-tossed family factions are reunited.

You could argue, and some have, that this focus on the problems of a single (wealthy, Western) family runs counter to the movie's spirit, but I didn't feel the final scenes undid what Bayona accomplished in the first two-thirds of "The Impossible."

And they certainly don't hurt Watts' chances for a Golden Globe.