Something — some thing — is terrifying the good folks of Lillian, Ohio, but what is it? A gas-station attendant, his face blanched with fear, sees it and screams; all we see is his body being jerked out of the frame. A telephone lineman on his crane hears it as a clattering clank of metal, like a clumsy heist at Home Depot; soon he's gone. But the creepiest hint that a nasty creature lurks in Lillian comes when 12-year-old Joe (Joel Courtney) posts a notice about his lost dog on a public bulletin board and the camera pulls back to reveal a hundred posters of missing pets. Who, or what, took the dogs out?

J.J. Abrams, writer and director of the scary, artful new thriller Super 8, is a hoarder of secrets, a master in the fine art of withholding information. Fans of Lost, the TV series he co-created, had to stick around six years for its mysteries to be revealed. "J.J. makes the audience wait for it," says Steven Spielberg, a producer and abettor of Super 8. With a conjurer's practiced blandness, Abrams simply says, "I believe in anything that will engage the audience and make the story more effective." But the man is no sadist. He, more than anyone, loves not knowing what comes next. As a boy, he bought a mystery box at a Manhattan magic store; now 44, he still has the box and still hasn't opened it.

The mystery box in Super 8 is a boxcar on a freight train speeding through Lillian one night in 1979 as some kids are furtively shooting a Super-8 movie. Pudgy Charles ?is the director, with the quick mind, bossiness and vast reserves of movie lore that mark a budding auteur. Cary puts his pyrotechnic and possibly pyromaniacal skills to use as special-effects wizard. Joe does makeup and constructs the models that Charles' action film will crash. But like any nebbishy guys, these kids are making movies to attract the ladies — specifically their leading lady, Alice , a 14-year-old blonde with an imperious star quality. As Joe powders her face for the shoot, he gazes at her with naked adoration, perspiration forming on his brow like evening dew.

In the middle of their big take, the train crashes into a car on the tracks, spraying tons of debris their way and sending a platoon of military men fanning out across the scene. Only Joe has noticed that the car was driven onto the tracks, seemingly in a suicide mission. In the car is the boys' science teacher, injured and near death. "They will kill you," he mutters. "Do not speak of this or else you and your parents will die." Do not speak of what? Of the thing that none of the kids saw — the some thing that has escaped.