Summer bummer?

There's a warning at the tender, bruised heart of (500) Days of Summer, kind of like an alarm on a clock-radio set to MOPEROCK-FM, going off somewhere in another room. Probably a room with the blinds closed, the nightstand littered with empties and Hostess wrappers, and a tender, bruised-hearted young man curled up in bed with three days of depression stubble growing on his face.

The alarm has been set for our protagonist, the above-described ill-shaven swain, but also, no doubt, for a goodly number of delusional souls in the darkened movie theater, sitting in blissful proximity to their imaginary soulmate the next seat over. Setting a terrible example for them is Tom (Joseph Gordon-Levitt), a student of architecture turned architect of sappy greeting card messages, who opts to press snooze and remain in the dream world of "I'm the guy who can make this lovely girl believe in love."

The agnostic in question is a luminous, whimsical creature named Summer (Zooey Deschanel), who's sharp enough to flirtatiously refer to Tom as "Young Werther" but soft enough, especially around a pair of oceanic blue eyes, to seem capable of reshaping into a true believer. Her semi-mysterious actions throughout (500) Days raise the following question, though: is a mutual affinity for Morrissey and Magritte sufficient predetermining evidence of what is and is not meant to be? Over the course of an impressionistic film that flips back and forth and back again through the title's 500 days, mimicking the darting, perilous maneuvers of ungovernable memory, first-time feature director Marc Webb and screenwriters Scott Neustadter and Michael H. Weber answer this and related questions in a circuitous fashion, while gently querying our tendency to edit and manufacture perceptions.

File under romantic comedy, for lack of a category for charming interventions on behalf of dreamy-eyed victims of willful self-delusion and pop culture. There's certainly plenty to laugh at here, such as a postcoital scene involving a choreographed jazz-dance routine through downtown L.A., set to Hall and Oates' "You Make My Dreams Come True." But other, swoonier songs and scenes produce a more poignant effect, and Gordon-Levitt's dead-on depiction of his character's romantic travails perfectly evokes the sensation of an enduring, unwise crush, the longing like a weight on one's heart, and the intractable, bittersweet memories that, no doubt, have kept many a viewer awake at night.

(500) DAYS OF SUMMER opens Fri/17 in San Francisco.