(CNN) -- For filmmakers, the private life of Henry VIII is the kind of history lesson that writes itself: sex, adultery and decapitation, right there for the taking.
Anne and Mary Boleyn (Natalie Portman and Scarlett Johansson) vie for Henry VIII in "The Other Boleyn Girl."
Perhaps that's why 500 years later, we still can't get away from the Tudors -- which is not to say this history can't stand some "improvement."
Based on a novel by Philippa Gregory, "The Other Boleyn Girl" grafts a purely speculative sisterly rivalry on to the familiar tale of Anne Boleyn's determination to become Henry's new queen.
It's a fact that Mary Boleyn (who may or may not have been younger than her sister) became the king's mistress in 1519 or so, while he was married to Catherine of Aragon. In the movie, Henry (Eric Bana) transfers his affections to Anne (Natalie Portman) after Mary (Scarlett Johansson) is laid up, pregnant with his child.
Headstrong and resentful after being overlooked the first time round, Anne sets about ensnaring the king in his own lust. If he wants her (and she makes sure that he does) he's going to have to marry her. Watch the stars talk about the film »
Although it's being sold as a classy bodice-ripper, the movie is less sexed up than Showtime's "The Tudors" and less souped up than last year's "Elizabeth: The Golden Years." It could be regarded as an unofficial prequel to that movie, as Anne Boleyn was Elizabeth's mother. Still, sex is central to the tragedy, and so is class.
Gregory and screenwriter Peter Morgan, fresh from his courtly duties on "The Queen," take aim at a callous patriarchal society where arranged marriages are the ticket to prosperity and political advancement.
The girls' father, Thomas Boleyn (Mark Rylance), and his brother-in-law, the Duke of Norfolk (David Morrissey), conspire to dangle them before Henry in the hope that one will take his fancy. Even a brief spell as the king's mistress could mean riches for the family and a favorable marriage afterward.
Anne's personal ambitions trump her father's. The high-stakes game she plays is altogether more dangerous and defiant, and she thinks nothing of altering the rules as she sees fit.
If this makes her sound like a proto-feminist martyr, the movie's sentimental heroine is actually Mary, who aspires to nothing more than a love match and a quiet life in the country. Pallid and fretful, Scarlett Johansson struggles to make virtue and loyalty compelling attributes, and the movie might have worked better if the roles had been reversed.
Natalie Portman has some good moments, particularly later on as Anne realizes the trap she's made for herself, but it's hard to believe this eminently sensible, even-tempered actress getting herself into such hot water, and even harder to care.
Author Gregory's Anne is conniving and calculating. But she is also composed a large part of Scarlett O'Hara: impetuous, impudent and a natural flirt. None of this comes naturally to Portman, who is no one's idea of a witch. And no, she doesn't play the role with six fingers -- a legend about Anne that probably isn't true -- either.
As for Henry, Eric Bana glowers and broods on cue, but save for two sex scenes, one romantic (with harp strings!), the other brutal, he doesn't have that much to do.
Director Justin Chadwick is a graduate from the BBC's acclaimed "Bleak House," and these roots in "Masterpiece Theatre" show. Chadwick shies away from the big picture; instead, he keeps things moving without chancing any of the voguish flourishes Sofia Coppola laid on "Marie Antoinette," for example. The upholstery is perfectly fine, but the look is intentionally overcast and constricting.
The dialogue, too, is more functional than memorable, with the notable exception of Anne's last words, a vivid flash of eloquence that comes straight from the historical record.
More poetry, wit and audacity would have been welcome, or more ripped bodices for that matter. Anything to liven up a drama that repeatedly falls between the tortuous power play everyone seems to think they're making, and the romantic potboiler that keeps peeking through the curtains. Either will have to wait for "The Other Boleyn Movie."