IF "BRIGHT Young Things" were to slow down, darlings, it probably wouldn't hold up under scrutiny. Like a skimming stone -- or better yet a flapper breezing through her first party on a long Saturday night -- the momentum is part of the thrill.

Stephen Fry's engaging, energetic film, based loosely on Evelyn Waugh's 1930 "Vile Bodies," fairly whizzes along its own surface. It's about the rich, young and restless of the 1930s who dance and party as London looks on in appalled dismay. And while their champagne-sipping debauchery soaks up the society pages of Fleet Street, the world teeters at the edge of world war.

Adam Fenwick-Symes (Stephen Campbell Moore), an ambitious English writer just in from France, is in a beastly dither. His first novel, which was commissioned by Canadian publisher Lord Monomark (Dan Aykroyd), has been confiscated. It seems the stuffy customs officer at Dover took umbrage at the title of Adam's manuscript ("Bright Young Things") and his witty pseudonym, Sue de Nimes.

Now without means -- he had high hopes for that book and Lord Monomark wants his money back -- Adam tells his girlfriend, Nina Blount (Emily Mortimer), he can't afford to marry her. In shame, he checks into a rundown hotel, where he immediately reverses his fortune. Outwitting a hustler at his own game, he wins a bet and finds himself with a thousand pounds. But no sooner has he informed Nina the wedding's back on, he loses his money again, to a drunken major (Jim Broadbent) who swore he could put Adam's money to work on a sure bet at an upcoming horse race.

Penniless again, Adam's more than receptive when Lord Monomark recruits him to be his gossip columnist, infiltrating the world of the rich and aimless. Not very good at gaining access, Adam starts to fabricate characters and situations; he even claims to have discovered a new fad: green bowler hats.

The story, with its quasi-farcical plot, may be nothing to write home about, or even pen a gossip column over, but "Bright Young Things" exults in its own giddy absurdity. Adam's social standing soars and plunges like the stock market, even with Nina, supposedly his romantic ally. She seems quite prepared to marry or drop him, depending on his money situation. And her bottom-line morality makes her very susceptible to the advances of Ginger Littlejohn (David Tennant), a childhood friend who has come into money.

When Nina sends Adam to ask her father for a loan, her hapless boyfriend finds himself face to face with the abrasively eccentric Col. Blount (Peter O'Toole). At first he mistreats Adam, mistaking him for a salesman. Then, after realizing his mistake, welcomes him and even writes him a fat check. Or does he? Adam discovers Col. Blount has a special trick up his sleeve.

Blount is one of several funny characters, including the elusive major and Agatha (Fenella Woolgar), a diehard party girl who finds herself, one hung-over morning, trying to breakfast with the disdainful prime minister (Bill Paterson). Agatha, you see, stayed over with the prime minister's partying daughter the night before; and now she's stuck making conversation with the priggish PM, with only her own flapper catchphrases and socialite ways to help her. It's a wonderful, disastrous encounter. Her clueless frivolity and increasing discomfort are divinely excruciating and, thanks to Fry's blithe spirit, discomforting fun.

BRIGHT YOUNG THINGS (R, 105 minutes) -- Contains drug use. At Cinema Arts Theatre, Cineplex Odeon Shirlington, Landmark's Bethesda Row, Cineplex Odeon Dupont Circle.

Stephen Campbell Moore and Emily Mortimer in Stephen Fry's effervescent 1930s-era "Bright Young Things."