I'm always thrilled to see a film that defeats my expectations because it's already decided on its own plan, its own world, without even a nod to convention. Quentin Tarantino's "Pulp Fiction" was one; Tom Tykwer's "Run Lola Run" was another, and now I see elements of that go-to-hell mentality in the new film "Juno." "Juno" is a film that might have been as slimy and predictable as "Knocked Up," or even an after-school special about pregnant teenagers; instead it charts a quirky course that mixes delight at what we see on screen, together with some deeper implications that have relevance for us all.

And it starts with its star, the brilliant and quirky actress Ellen Page, who plays the 16-year-old Juno and makes you wish you were lucky enough to have her as your own daughter. She is wonderfully bright, articulate, and totally without self-consciousness. She and her best friend Paulie (Michael Cera) have had one moment of unprotected sex, in fact it was their only moment; and of course she is now pregnant. After visiting an abortion clinic she decides to carry the baby. Her friend Leah (Olivia Thirlby) tells her that there are ads by couples looking for a child; she finds an upscale yuppie couple, Vanessa and Mark Loring (Jennifer Garner and Jason Bateman) who've been looking for a child to adopt. And who as the date gets closer find their marriage falling apart and the husband revealing a creepy side to himself.

I guess what I haven't told you is what happens in the interstices of the plot, which is what makes this film so delicious: Juno has the wit and the wisdom to see herself without any kind of blinders or facade; she is thoughtful and understanding of both herself and the others. She has a wonderful, almost jokey way of expressing herself without resorting to some kind of deep truths about pregnancy. And she's blessed with a father and stepmother (J.K. Simmons and Allison Janney) who don't panic. Simmons to Janney: "Did you see this coming?" "Sure, but I thought she'd been expelled, or caught with drugs, or a D.W.I."

But there are so many unexpected moments: the young pharmacist who's not upset or moralistic; the high-school cross-country team that runs through every other scene (Paulie is on the team), the charming songs on the sound track, the way in which this is not treated as a life-altering event. Page has been given a script by Diablo Cody that simply rings true on every level, and she's found just the right note for every line in it. The direction by Jason Reitman is competent without trying to muscle itself in by calling attention to itself. But the ultimate joy of the film is Ellen Page herself; what a find she is!