"The Odd Life of Timothy Green" is a refreshingly old-fashioned flick.

Those might seem like odd words to put together. But so many family films these days rely on over-the-top special effects and saccharine musical numbers to provoke emotion that it comes as a surprise -- a very pleasant surprise -- to see something so simple. "Timothy Green" is very much like a fable or a fairy tale, the sort of story that's been charming children for centuries. It doesn't reinvent the wheel, no. But in a summer of overblown entertainment, it stands out.

Cindy (Jennifer Garner) and Jim Green (Joel Edgerton) have been trying unsuccessfully to have a child, and doctors have finally told them to give up. Cindy is determined to move on. But Jim finds it hard. "Just for tonight," he asks his wife, "can't we have a kid?" They spend the evening writing down all the qualities they would have wanted their child to have. Then they stuff the pieces of paper in a box and bury them in their backyard.

Those notes mysteriously, magically turn into the very child they describe. Timothy Green (CJ Adams) shows up in their yard fully formed. The 10-year-old calls Cindy "Mom" and Jim "Dad." He can't explain how he came to the Greens. And the Greens, having had their most-wished dream come true, decide not to look a gift horse in the mouth.

Yes, it's a preposterous premise -- but no more absurd than the story of Jack, the boy who planted some magic beans. What makes this story leap from the screen isn't its plot -- you can predict most of it -- but the lessons learned by the characters we meet. Garner and Edgerton play appealing everymen who want to be that mythical thing, the perfect parents. "Have a great day!" Jim calls out to Timothy on the kid's first day of school. "That's too much pressure," Cindy whispers. "Have the day you have!" Jim then shouts, in the same upbeat voice.

Adams is impossibly cute and has real talent. His Timothy is knowing and innocent at the same time, a hard mix for anyone to capture. This young actor has a lot to do here. Not just Cindy and Jim, it turns out, but their entire, struggling small town needs to understand what Timothy was sent there to tell them: Anything is possible if you believe.