Shot in the bitter cold of rural southern Ontario on a modest budget of $4 million Canadian (Lionsgate has picked up distribution), this thoughtful, measured film about the slow drift of memory and marriage has received excellent notices at a string of film festivals, and opened in New York and Los Angeles two weeks ago, before rolling out across the country later in the month. (The film opens in Salt Lake City today.)

Polley read the short story in The New Yorker on a plane ride from Iceland in 2001, where she had just finished shooting the Hal Hartley celebrity parable "No Such Thing." She was in the early stages of a relationship with the man who would become her husband, a Toronto film editor named David Wharnsby. By the time she landed, Polley had conceived the film version of the story in her mind as an investigation into the longevity (and, within that, the cruelty and grace) of love.

"I think we have a really hard time culturally with what happens to love after the first year. It is difficult, and it is painful, and it is a letdown," said Polley, who married in 2003. "That first year is so much less profound than what happens when you're actually left with each other and yourself in an honest way. It was interesting to me to make a film about what love looked like after life had gotten in the way, and what remained."

High-minded literary adaptations are not the most common conclusion to the child-star story, but Polley's short life is a narrative of surprising, sometimes brutal swerves.

She comes from a creative Toronto family with five children headed by a casting-director mother, Diane, and an actor father, Michael (currently seen on the Sundance Channel's theater satire "Slings and Arrows," on which Sarah Polley makes occasional, uncharacteristically comedic appearances). The family mythology maintains that Sarah was an acting-obsessed toddler who grabbed scripts off the coffee table and demanded auditions, landing her first role at age 5 in the film "One Magic Christmas."

While Polley does not blame her parents for failing to dissuade her, she said that she would never allow her hypothetical children to perform professionally. "When an 8-year-old wants to become a fireman, you go, 'Look, go and play with these toys and pretend you're a fireman.' Why do we let kids who want to act become actors?"

At 8, Polley played the urchin Sally Salt in Terry Gilliam's "Adventures of Baron Munchausen," which also starred Robin Williams and Uma Thurman in small roles. For her, the experience was traumatic: 18-hour days on a set in Spain, and hospital trips for hypothermia and an irregular heart rate caused by an explosion that went off near her head.