Super 8 is a model of recycling. Its director, JJ Abrams, salvages the best parts from Steven Spielberg blockbusters. Because Abrams likes his melancholy characters and lets them be awestruck and aw-shucks, it works.

It takes place during the summer of 1979, the twilight of America's industrial dominance. Virtually every scene mourns the obsolescence of the American-made as it simultaneously celebrates American ingenuity.

Accordingly, this likeable sci-fi mystery is set in an Ohio rust-belt town at roughly the time the Walkman displaced transistor radios and slightly before the Betacam superseded the home-movie camera. The film takes its title from the device used by six pubescents to shoot a zombie movie over their summer vacation.

A menace stalks both the movie and movie-within-the-movie. Difference being that the one stalking the movie is for the most part heard rather than seen. One night way after bedtime, as the young filmmakers stealthily shoot a scene at a nearby station, a cargo train derails. The iron clang of a scrapheap magnet and the metal crunch of crumpled steel unnerve the young filmmakers.

They include sad-eyed Joe Lamb (newcomer Joel Courtney), age 12, the model maker and makeup artist on the student film, and sadder-eyed Alice Dainard (Elle Fanning), 14, the slender blonde upon whom he has a crush.

While the blood on the tracks is mostly from Joe's prop bag, some of it belongs to his science teacher, Dr. Woodward (Glynn Turman), whose truck was sideswiped by the hurtling train. "Do not speak of this!" he warns Joe, who scavenges through the wreckage and pockets a mysterious white cube that resembles a life force imprisoned inside a Rice Krispies treat.

The unforced performances of Courtney and Fanning are remarkable, personifying the universal adolescent condition of wanting equally to stay in the cocoon of the bedroom and also to strike out on an adventure into the unknown. Because their characters are so finely drawn and deeply felt, the movie's mystery becomes almost superfluous.

An uninterrupted sequence where Alice acts with exquisite seriousness while the Super 8 camera is running and goes goofy when the camera stops is very funny and very dear.

The film's major flaw is that Abrams plays the heartstrings with considerably more finesse than he does the adrenal glands. The worst that can be said about the film is that the characters are far more compelling than the mystery they solve.