Somewhere in the publicity for "(500) Days of Summer," I read that it's not a love story but instead is a story about love. I wish I'd thought of the line myself, because it perfectly describes this charming movie.

Except for one thing: It fails to mention that love can hurt really, really bad.

Ask Tom Hansen. He's the character who discovers that Cupid's arrows can be poisoned. The object of his affection or obsession or love or lust or all of the above is Summer Finn. Tom is a would-be architect who supports himself by writing greeting cards for a Los Angeles company. Summer is assistant to the boss. From the moment he first spots her, poor Tom's a goner.

They start keeping company. And a darned cute couple they are, playing house in IKEA, going to art shows and movies, canoodling and whatnot. The leads are portrayed by Joseph Gordon-Levitt and Zooey Deschanel, who have chemistry to burn.

But there's a fly in the love potion: Tom, a romantic, wants it to be a Relationship, preferably one leading to marriage. To Summer it's an entertaining fling and to her credit she never pretends anything else. As one of Tom's buddies puts it, Summer thinks like a dude!

Tom is train-struck when it ends -- and it does end, early in the movie. That's not giving anything away; remember, it's a story about the bittersweet mysteries of love rather than a romantic comedy in the usual sense. The movie is about why the romance tanked and what happened afterward. There's even an upbeat conclusion, though it seems a bit contrived.

Aside from the unusual candor and the leads' terrific performances, "(500) Days of Summer" succeeds because of Marc Webb's stylish direction and the smart and funny script by Scott Neustadter and Michael Weber. Webb throws everything into the pot -- split screens, a dance number, animation, mock documentary black-and-white sequences -- and makes it work. It's his first feature after a career in music videos.

The screenplay tells Tom's and Summer's story not in conventional narrative form but by hopscotching back and forth among the 500 days of their non-Relationship relationship. In fact, you could say it starts at the end. The technique isn't exactly new, but seems fresh because it's so perfectly attuned to the vehicle at hand.

There are a few false notes. One is the aforementioned ending, which is a bit too cute. Another is Tom's practice of consulting his pre-teen sister for advice. C'mon, guys. Middle-schoolers are good at computers and skateboards, not advice to lovelorn adults. There's a slight imbalance, too, between Tom's architectural ambitions and Summer's apparent lack of interest in anything beyond the moment.

But where "(500) Days of Summer" really shines is in comparison with conventional (read: predictable) Hollywood romantic comedies. I saw "The Ugly Truth" recently and remember writing that it was OK for what it was. Next to "(500) Days of Summer," that isn't much.