Would you know what to do in the wake of a nuclear attack?

Me neither.

But I learned far more than I ever wanted watching Aftermath, an oppressive, thoroughly depressing thriller about nine strangers who take shelter in a basement following a nuclear holocaust.

Thriller might be the wrong word.

There's very little that actually thrills in this well-constructed, if underwhelming film that works best as a how-to vid for nuclear war-minded DIYers. It should have been shown to kids in the 1950s instead of those goofy educational shorts that pretended you could survive a nuke by hiding under your desk.

It would be a sobering exercise, since Aftermath has one lesson: No matter what you do, if you've been exposed to radiation, you'll die an ugly, agonizing, generally horrible death.

C.J. Thomason (Harper's Island) stars as Hunter, a brilliant New York doctor backpacking across rural Texas when global war breaks out. One second he's strolling in a lovely, overgrown field, the next he's on his belly under a car as two massive blasts go off in the distance.

Mushroom clouds form over each.

A harbinger of death.

His death? The death of his loved ones? The audience's death?

Without a moment's hesitation, Hunter goes into can-do mode. Well aware that nuclear explosions release electromagnetic pulses that fry all electronic equipment, he knows what kind of vehicle still works (older diesel cars and trucks); he knows exactly which supplies to grab from the store, and what kind of underground shelter to find, how to seal all its cracks and bury the entrance under dirt.

A born hero, he rescues a woman named Jennifer (Jessie Rusu) and her little brother Satchel (Kennon Kepper), stranded on the road.

By and by, the three find themselves holed up with six other people in a farmhouse cellar. Hunter calls the shots, telling the assembled they have to stay there at least a month.

So the clock starts ticking.

Title cards announce each passing day -  Day 1,  Day 4,  Day 12 ,  Day get-me-the-heck-out-of-here! - as we watch the men and women lose their minds or succumb to radiation poisoning.

Films of this ilk - claustrophobic, one-set survivor yarns pitting strangers against one another - live or die by their dialogue and characterizations.

The paradigmatic example, Hitchcock's Lifeboat, had a streak of devilish humor and characters so different from one another they were bound to clash.

For its part, George Romero's Night of the Living Dead - featuring a tense scene in a farmhouse basement - was soaked with such surreality, one could excuse its lumbering pace and weak storytelling.

Aftermath doesn't quite pass the acid test. The dialogue is rarely compelling, the character work minimal. The people are far too much alike: Seven of the nine survivors are white, middle-class, and in their late 20s or early 30s.

With the possible exception of Hunter, they are not terribly interesting, much less enigmatic. And their interactions don't make for much tension, unless you consider a few hissy fits thrown by costar Edward Furlong's redneck yokel Brad to be the sign of great cinema.

If you must see Aftermath - perhaps for its helpful advice on how radiation sickness works - wait for the DVD.

Aftermath ** (out of four stars)

Directed by Peter Engert. With C.J. Thomason, Edward Furlong, Monica Keena, Andre Royo, Christine Kelly. Distributed by Image Entertainment.

Running time: 1 hour, 32 mins.

Parent's guide: No MPAA rating (adult subjects, profanity, disturbing images).

Playing at: AMC Loews Cherry Hill 24.