IN "TUNE IN TOMORROW," Peter Falk is an oddball scriptwriter who lights a fire under New Orleans in the 1950s with his sizzly radio soap operas full of passion, incest, intrigue and other vicarious enticements.

A tremendous seriocomic performer -- from "The In-Laws" to the "Columbo" series to his memorable angel's role in Wim Wenders's "Wings of Desire" -- Falk is easily the best thing about this production. But in director Jon Amiel's version of Mario Vargas Llosa's "Aunt Julia and the Scriptwriter," the movie spends too much time with the Aunt and not enough with the Scriptwriter.

Barbara Hershey, who plays the Aunt, doesn't turn out a bad performance so much as an ineffective one. She and Keanu Reeves, whose affair is supposed to be "Tune In's" main attraction, manage to be the least interesting people in New Orleans. She's an eccentric widow. He's a fledgling radio writer at WXBU, and her nephew by marriage, who becomes obsessed with her. But this older-woman-eager-lad affair leaves the Crescent City and heads straight for Dullsville in a hurry.

Falk, meanwhile, has just joined Reeves's station, where his steamy transformation of the lackluster series, "Kings of the Garden District," is causing wide-eyed people to cluster around their radio sets. For reasons best known to himself, he's also throwing in gratuitous slurs against Albanians whenever possible. Albanians are getting mad. So is Reeves, whose personal life keeps suspiciously showing up in Falk's scripts.

The excitement, however, only kicks in when Falk's onscreen. A blustery fusion of amusement and menace, he's a salty tongued, subversive element and steals every scene. One of his kicks is to find endless variations on the Is-the-Pope-Catholic?-type response, the most printable being "Do bears do big poody in the woods?"

If you're looking for the dark brilliance of director Amiel's BBC series, "The Singing Detective," or the magical appeal of his "Queen of Hearts," you'll find it in fits and starts. The opening credits, for instance, are announced in good ol' radio style by Henry Gibson, rather than shown in titles. There are also some marvelous flittings between fantasy and reality, as the movie cuts from people tuned in to the "Garden" series, to the soap characters (played by Buck Henry, Elizabeth McGovern, John Larroquette and others) acting out the stories.

But those moments are far too rare. In this Americanization of Vargas Llosa's Peru-based story, Amiel and screenwriter William Boyd have tuned in to the wrong frequency.

TUNE IN TOMORROW (PG-13) -- Area theaters