In storytelling, especially in filmmaking, once the plot takes a wrong turn there's no going back. And more than a few promising movies have started out well only to spoil things with an unsatisfying conclusion.

Two new films exemplify the perils of inconsistent plotting, though in both cases the directors could blame the authors for story-telling blunders, since they are based on well-known novels:- "OSCAR AND LUCINDA" could be expected to be slightly off-center, given the quirkiness of its source material (Peter Carey's bittersweet novel) and the eccentric mixture of themes (love, religion and gambling addiction). But even warm performances from leads Ralph Fiennes and Cate Blanchett can't overcome the cold, off-putting direction of Gillian Armstrong ("The Piano") or the film's preposterous second act.

Fiennes stars as Oscar Hopkins, a young Anglican minister in 19th century England. Though Oscar is a firm believer in the existence of God, he also has a dark side - he is addicted to gambling, especially betting on horse races.

To gain some sort of redemption, he sails to Australia to become a missionary and immediately replaces the disgraced Rev. Dennis Hasset (Ciaran Hinds). However, temptation comes calling again, this time in the form of Lucinda Leplastrier (Blanchett), a young Australian heiress who also spends much of her time gambling.

Once two meet, they quickly indulge in their passion for wagering. They also share another sort of passion - romantic, though it goes unspoken.

Desperate to prove his love to Lucinda - who he believes is in love with the Rev. Hasset - Oscar agrees to spearhead a dangerous expedition to New South Wales and to present the good reverend with a glass church that Lucinda has made for him.

Similar in spirit (but not execution) to the quest in "Fitzcarraldo," the film's second half is messy and spoils the whole thing with a series of ludicrous plot twists, as well as violence and sex that are shocking in comparison to the restraint shown earlier in the movie.

As mentioned, both Fiennes and Blanchett are fascinating to watch, though their characters make decisions that seem, well, awfully out of character.

"Oscar and Lucinda" is rated R for violence, a surprisingly graphic simulated sex scene, nudity, some vulgar references and gags and some scattered profanities.

- "PALMETTO," a dark comic thriller, is, in its way, almost as disappointing - especially since it so deliriously sends up the noir film genre during its first hour.

Unfortunately, things go as awry here as in "Oscar and Lucinda" with a turn toward the absurd at the end that pays obvious homage to "Sunset Boulevard" - but in a truly bewildering way.

As with most films of this particular genre, the lead character is a dope who thinks he's smarter than he is. This time, it's Harry Barber (Woody Harrelson) who gets in way over his head when he falls in with the wrong crowd.

Having been recently released from prison, the former newspaperman has a chance to go straight with his faithful artist girlfriend, Nina (Gina Gershon). But wouldn't you know, he instead meets Rhea Malroux (Elisabeth Shue), a beautiful, mysterious blonde who has a business proposition for him.

Rhea and her vixenish stepdaughter Odette (Chloe Sevigny) are conniving to swindle their husband and father, millionaire Felix Malroux (Rolf Hoppe), out of $500,000. They plan to fake a kidnapping of Odette, and they need Harry to provide the threatening phone voice.

And the money drop-off seems to go OK, but when Harry returns to his hideout to count the loot, he gets a rather unpleasant surprise - Odette's body on the bed. So he goes on the lam. From there, things go downhill.

Veteran director Volker Schlon-dorff ("The Tin Drum"), making his first real attempt at "mainstream" filmmaking, has a pretty firm grasp on things until they're undone by E. Max Frye's muddled plotting.

And though almost everyone in the cast is good (especially Gershon and Sevigny), Harrelson's a little too good at playing the dumb guy. And Shue's bit at the end mars an otherwise subtle turn.

"Palmetto" is rated R for violence, profanity, simulated sex, vulgar sex talk and references, gore and brief female partial nudity.