I'm a teen - get me out of here!

After a spate of boy-targeted pirate and "Terminator" fare, teenage girls are bidding for attention this week. The favored age is 17, which is how old the heroines of "How to Deal" and "I Capture the Castle" happen to be.

Although both pictures are romantic comedies of a sort, the modern-day "How to Deal" is actually harder to believe than "Castle," set several decades ago, where the heroine lives with her weirded-out family in an exotic fortress. This isn't because "How to Deal" is more far-fetched, but because its teens behave less like real adolescents than like the plot-driven youngsters Hollywood is prone to dreaming up.

The big selling point of "How to Deal" is Mandy Moore, the popular singer and rising movie star whose public image is a sort of Britney Spears without the glitzy outfits and aggressive sexuality.

Ms. Moore plays Halley, a well-meaning girl with the kind of dysfunctional family film teens almost always seem to have. Her mom (Allison Janney) is still quaking from a recent divorce; her DJ dad (Peter Gallagher) is marrying a bimbo half his age; her grandma (Nina Foch) enjoys sneaking to the bathroom for pot-smoking sessions; and her big sister (Mary Catherine Garrison) is engaged to a guy who doesn't think a day is complete with at least one major squabble.

And then there's her best friend, another teen (Alexandra Holden) whose boyfriend meets an accidental death immediately after getting her pregnant. Halley really likes Macon, the handsome boy (Trent Ford) who wants to date her. But with so much love-related misery swirling around her, how can she help being cynical about the very idea of romance? Can she be "just friends" with Macon, or is even a platonic relationship too risky for a girl who thinks "falling in love" mean just that - falling, falling, falling, with a rocky crash as the inevitable result?

While it's a romantic comedy on the surface, "How to Deal" is really more like a TV soap opera, hinging its story on quarrels, accidents, death, and unwanted pregnancy. There are light and amusing moments along the way, of course, but director Claire Kilner and screenwriter Neena Beber don't walk the tightrope between comedy and drama skillfully enough to make either aspect work as well as it should. Nor do they let characters talk their problems through in thoughtful, intelligent ways. Instead there's lots of grumbling, lamenting, and dithering in scenes that always run a little too long.

I'm sure many youngsters will find their own hopes, fears, and longings mirrored in the tale's many twists and turns. But there's not much insight into what really makes teens tick, and that's what keeps "How to Deal" from being the supportive, compassionate yarn it tries so hard to be.

From its title, you'd think "I Capture the Castle" is another of the summer's many action-adventure epics. In fact, it's the opposite - a story of teenage love and domestic drama that's aimed primarily at adolescent girls but should appeal to open-hearted audiences of all ages.

The heroine is Cassandra, a 17-year-old facing (you guessed it) lots of family problems. Her father, James, is a once-successful novelist who hasn't finished a new book - or written a clever sentence, for that matter - in 12 years.

Her older sister Rose is a chronic complainer, and their new stepmother is amiable but as eccentric as they come, even in 1930s England, where eccentricity is a valued commodity.

Two things loom over all of them. One is the searing memory of the worst day in the family's life, when James attacked the girls' mother (now dead from unrelated causes) with a murderous anger that might have proved disastrous if his weapon had been more effective.

The other is the home where they now live: an ancient castle where James ensconces them in the vain hope it'll inspire him to write the masterpieces that have been eluding him for the past decade or so. It doesn't take a literary genius to figure out that the place's initial charms - antique architecture, enigmatic carvings, a sense of history - will soon give way to the irritations and frustrations of leaky walls, drafty passageways, and a total lack of modern conveniences. Even if they had a radio, there'd be no place to plug it in.

On top of this, the household is impoverished and the rent is overdue by two years. Can anything save Cassandra and Rose from eviction and homelessness? Enter two American brothers: Simon, who now owns the castle, and his business-minded brother, Neil, who wants to evict the current tenants.

Determined to avert this fate, Rose sets out to make Simon fall in love with her, despite the fact that she doesn't fancy him a bit. Her plan works, but hints of romance have been blooming between Simon and Cassandra as well, auguring a complicated future, if not a catastrophic one.

In his feature-filmmaking debut, Tim Fywell has directed "I Capture the Castle" with a refreshing lack of grandiosity, coaxing first-rate performances from most of the cast - headed by Romola Garai as Cassandra and Henry Thomas as Simon - and also from the castle, whose gloomy atmosphere fends off the sentimentality and overstatement that occasionally threaten to capture the movie. It's surprising no filmmaker has adapted Dodie Smith's novel before now, and pleasing that Mr. Fywell and company have done such a responsible job with it. It's one of the season's most captivating surprises.

• "How to Deal," rated PG-13, contains profanity, sensuality, and drug use. "I Capture the Castle," rated R, contains nudity and sensuality.