Pat Conroy's novel "The Lords of Discipline" was anything but a disciplined novel; the new film version, directed by Franc Roddam, the British director who made an impressive debut with "Quadrophenia," spares moviegoers a prolonged exposure to Conroy's feverish account of Movies sadism, betrayal and triumphant selfrighteousness in the setting of a Charleston, S.C., military academy in the mid-'60s.

Roddam and his screenwriters jettison quite a bit of expendable exposition, notably a romantic subplot of dumbfounding dippiness, but they still can't compensate for the fact that Conroy mislaid the central plot element--the struggle to unmask and discredit a secret society of upperclassmen, known as The Ten, who have dedicated their despicable efforts to railroading the first black cadet at Carolina Military Institute out of school.

The story seems to reach a turning point when the hero, a misfit but upstanding senior named Will McLean, discovers The Ten's secluded torture chamber. Col. "Bear" Berrineau, the gruffly incorruptible commandant, had assigned McLean to keep an eye on the endangered plebe. But this central issue--the battle to uncover The Ten--inexplicably is reduced to a side issue.

Conroy struggled to whip up a new source of intrigue by pitting the hero and his loyal roommates in an unequal battle of nerves against The Ten and their shadowy patrons in the school administration. Miserably contrived, this shift in melodramatic emphasis hinged on a pretext that never made the slightest sense--Will's dopey, unfounded suspicion that the Bear might be playing him false. With Bear, a trustworthy and savvy figure of institutional authority, conveniently out of the picture for a spell, Will was permitted to blossom into a pulp fantasy college hero, a Boy Crusader of dazzling cleverness and outrageous sanctimoniousness whose exploits couldn't possibly have corresponded to Conroy's authentic experience as a misfit member of the corps of cadets. Will (the last name is altered to McClean by the moviemakers, presumably on a facetious whim) not only outfoxes The Ten but also exposes their protector, then reads the riot act to everybody who was nasty or devious, collects his diploma and righteously turns his back on the institute while still basking in the glow of boundless peer admiration and self-esteem.

When all was said and done, "The Lords of Discipline" simply was not to be believed. Although Conroy occasionally ridiculed his boyish alter ego for being an insufferable prig and salvation-hunter, he couldn't prevent the book from degenerating into a 500-page celebration of priggishness.

Most of the movie was shot in England, with only a smattering of location footage from the Charleston area. I'm not sure if something crucially authentic was lost by this dislocation, but the institute certainly seems more vague on the screen than it did in the book. At first David Keith appears a smart choice in the role of Will, since his diamond-in-the-rough personality contradicts the sensitive, bleeding-heart aspects of the character as written. As the plot unraveled, I became convinced that he'd been quite unfortunate in his first starring role. Far from counteracting the sanctimonious side of Will, he ends up diminished by the obligation to exult in it.

Moreover, the filmmakers lose track of things that Conroy specified, like the peculiar nature of Will's status on campus. Though a notorious malcontent and slipshod military figure, Will nonetheless enjoyed considerable respect as jock, student and member of the honor court. In the movie his credentials are reduced to innate decency and obligation to Bear, a role whose entertaining potential has been radically reduced from book to screen, a bad break for Robert Prosky, who had much better opportunities in "Thief" and "Monsignor." G.D. Spradlin, who is becoming the definitive character actor for authoritarian roles, contributes the only impressive performance as Gen. Durrell, the university president, at least until the script compels him to knuckle under to Crusader Will. It's really unfair to expect conscientious actors to authenticate such moments of delusionary moral one-upmanship. They may sound impressive when reverberating in writers' heads, but they defy credible enactment. Like "Lords of Discipline" itself, evidently.