"Pieces of April" is a Murphy's-Law Thanksgiving comedy in which both the meal and the movie have a hard time coming together.

Saddled with a handful of sitcomy plot contrivances that leave it struggling with its own mediocrity, the film's quirkiness never quite evolves into cleverness as it follows a pretty young punkette (Katie Holmes) through a day of near-disasters, and her uneasy suburban family on their long, reluctant car trip to her graffiti-encrusted Lower East Side walk-up for what they're sure will be a calamity of a holiday meal with their absconded black sheep.

While the nervous, habitually irresponsible April (Holmes) is banging on doors and meeting eccentric, snooty and non-English-speaking neighbors in a desperate search for a working oven (her own had served only as a cabinet until this morning, when she discovered it was dead), the girl's mom (Patricia Clarkson), dad (Oliver Platt), grandma (Alice Drummond) and teenage siblings are squeezed into a station wagon and getting on each other's last nerves.

Writer and first-time director Peter Hedges ("What's Eating Gilbert Grape?") has an good ear for the humorous dynamics of family dysfunction, capturing both April's short-fuse consternation over this rite of passage and her family's feelings of obligation that battle their acute aversion to pretty much everything that has to do with April. "All I can remember was the shoplifting, the fire in the kitchen, the drugs, the ingratitude," her mother gripes, adding ironically that "She bit my nipples whenever I tried to breast feed her."

Although some of that statement is hard to buy since Holmes seems like such a softie, the entire cast does a sublime job of finding comedy in their very real tension, which is exacerbated by the devil-may-care sense of humor Mom has developed as her body has been ravaged by breast cancer. But too often Hedges over-directs (in one scene it's patently obvious that Holmes has been instructed exactly when to pause mid-sentence to sip a drink) and he pads the 81-minute film with elements that feel forced and underwritten.

Why is April's boyfriend (Derek Luke) out shopping (at a closed Salvation Army with a friend who has the key) for a suit to wear to dinner on Thanksgiving Day? Why does April force a whole background story on every neighbor she approaches instead of just saying, "Are you using your oven today? Mine's broken and my family is coming." And why are some of those neighbors such ill-conceived clichés -- like the lapdog-petting, sweater-vest-and-watch-chain-wearing, effeminate, mock-erudite snoot so badly affected by "Will and Grace's" Sean Hayes?

The movie's heart is in the right place and its central characters are real enough that Hedges isn't afraid to make them a little hard to like -- especially April who is on the awkward cusp of adulthood but has the lingering ungratefulness of a self-centered child, even toward her more helpful neighbors. But with its strained satirical cuteness, its clumsy embellishments (which get worse toward the end) and its sophomoric overuse of in-camera visual gimmicks (overexposure, perspective-cam) this bird just tastes a little undercooked.