Its drugstore-rack roots intact, The Sentinel feels exactly like a paperback novel put to film. All plot, no theme, with quick-stroke characters who are both two-dimensional and larger than life, this adaptation of a novel by former Secret Service agent turned author Gerald Petievich does have the virtue of verisimilitude, lending the melodramatic goings-on the irresistible veneer of a look behind the scenes, inside the oval of power. It's no To Live and Die in L.A. (1985), the first and best adaptation of a Petievich potboiler, but it's certainly not Boiling Point, an adaptation of Money Man (1993) that was more like Bumbling Point.

Pete Garrison (Michael Douglas) is a semi-legendary Secret Service man. Wounded in the line of fire-to name a similar film-while protecting Ronald Reagan during John Hinckley's assassination attempt, he's an admired mentor who works in the West Wing, teaches classes at Quantico, and, though he's never climbed to the top rung, he does climb into the First Lady (Kim Basinger). Trysts happen. Former protégé David Breckinridge (Kiefer Sutherland, in total "24" mode) doesn't know about this one, but he does believe that Garrison, ten years earlier, had done some secret servicing of Mrs. Breckinridge. This causes some friction when Breckinridge's request for a Spanish-speaking agent gets him Jill Marin (Eva Longoria), a rookie whom Garrison helped train.

After an old and trusted informant gives Garrison a tip about a high-level plot to kill the President (David Rasche, who looks Republican but speaks in favor of the Kyoto Protocol), Breckinridge is in put in charge of the investigation. His guts tell him that the apparent street-crime murder of fellow agent Charlie Merriweather (played by the film's director, Clark Johnson, billed in the actors' credits as Clarque Johnson) is somehow connected-and as we know, these kinds of movies are all about guts and hunches since, to be fair, straight old deductive legwork is pretty dull unless you're Alan J. Pakula directing All the President's Men.

Complicating the Secret Service's hunt for the would-be killers-who the agents learn are being abetted by an unknown traitor within the Secret Service ranks-is a blackmail plot against Garrison and the First Lady, a dovetailing that helps paint Garrison as the treasonous cur.

It all moves pretty briskly. Johnson-a veteran actor-turned-director of TV's "The West Wing," "The Shield," "The Wire," "La Femme Nikita" and other cop/undercover/political shows, and the mediocre movie S.W.A.T.-doesn't linger on shots and goes from point to point to point with effective efficiency yet without showy, head-swiveling jumps; he's a director with enough confidence to be a straightforward storyteller and not indulge in visual junk food. He goes almost fast enough to gloss over the occasional plot-hole. (The security command center for a trade summit that the President's attending wouldn't have been sent Garrison's head-shot and a head's-up?) And he occasionally goes too fast, as with actress Blair Brown popping up now and then as some sort of presidential ball-buster. (Is she the Secretary of State? Is she the President's chief of staff? His executive secretary? Ohhhh, there it is in the credits...National Security Advisor.)

TV starlet Longoria is better than one might suppose as the rookie agent who quickly adapts. And she's at the center of a moment that by itself takes The Sentinel a notch above most such throwaway thrillers: When she shows up at Breckinridge's office for her first day there, the dyspeptic older agent assesses her Hollywood-standard, cleavage-baring professional uniform, and tells her to dress more appropriately. Verisimilitude veritas.

-Frank Lovece