"Halloween III: Season of the Witch," now playing at area theaters, abandons the stalking psycho formula of its predecessors for suspense devices borrowed from perkier, classier sources, notably "Invasion of the Body Snatchers" and the James Bond thrillers. Indeed, nothing becomes this sequel as much as the director's decision to steal more astutely.

Tommy Lee Wallace, an editor and production designer on John Carpenter's first four movies, including "Halloween," inherited several members of the Carpenter crew along with his producer, Debra Hill, and a leading man of ruggedly motley sorts, Tom Atkins, left over from "The Fog." The diverting, farfetched plot, set on the eve of a Halloween that threatens to erupt into gruesome national catastrophe, was evidently reworked and domesticated by Wallace from a screenplay first contrived by Nigel Kneale, a veteran British writer whose credits range from adaptations of "Look Back in Anger" and "The Entertainer" to science-fiction adventure thrillers like "Five Million Years to Earth" and "First Men on the Moon."

Atkins is cast, far from persuasively, as a small-town doctor who begins to suspect something funny is going on when a mysterious, zombieish assassin invades the sanctuary of a hospital to gouge out the eyeballs and empty the skull of a toyshop owner who is an emergency patient. Before the killer can be apprehended (not a wise thing to attempt, incidentally), he drenches himself in gasoline, lights a match and suffers the spectacular fiery consequences.

The puzzled doc forms an investigatory alliance, which quickly blossoms into an overnight love affair, with the victim's bereaved daughter (Stacey Nelkin, the voluptuous, doe-eyed knockout who played Bill Macy's playmate in "The Serial" and dressed up occasional moments in pathetic losers like "Goin' Ape" and "Up the Academy"), who suspects her dad's distress can be traced to a recent trip to the Silver Shamrock Toy Company to pick up an order of their popular Halloween masks. The suspicion is confirmed for moviegoers when the Silver Shamrock factory turns out to be in an ominously sleepy little community called Santa Mira, named after the fictional location in the first movie version of "Invasion of the Body Snatchers."

Pretending to be retailers, the hero and heroine put up at the local motel, where a neighboring guest fails to survive the night after blundering onto the hideous secret of Silver Shamrock's special line of fright masks for the Halloween trade. Nosing around the next day, the amateur sleuths become prisoners of the demented genius who runs Silver Shamrock, a diabolical Santa named Conal Cochran, portrayed with debonair, humorous nastiness by Dan O'Herlihy. It appears that nothing short of miraculous heroic intervention by the doctor can prevent the villain from activating a Halloween prank designed to murder millions of unsuspecting trick-or-treaters and their parents by televised remote control.

Nothing if not ambitious, this sick doomsday joke is elaborated in some outrageously funny ways -- for example, it involves the theft and transfer to Cochran's secret laboratory of an entire monolith lifted from Stonehenge -- and backfires on the mastermind in electrifying circumstances similar to the payoff spectacle in "Raiders of the Lost Ark."

If you've seen either version of "Invasion of the Body Snatchers," you'll also be several steps ahead of Wallace's penultimate plot twist and his fadeout kicker. To a considerable extent, the kicker is defused in advance by the director himself. It's obvious that he would probably prefer the movie to end about a reel before it does, with the maliciously witty hint that nothing can stop Cochran and that children all across the country are setting out on a Halloween night of disaster. Obliged to launch the hero on an effective counterattack down the stretch, Wallace goes through the motions proficiently enough for exploitation thriller purposes. He should have quit while he was ahead, but "Halloween III" demonstrates a reasonable ability to control comic-horror effects on his first derivative try.