The lyrical road comedy Y Tu Mamá También ("And Your Mother Too") suggests what one of those fraudulent the-summer-I-became-a-man movies might be like if it were made by someone with imagination and sensitivity. The director is Alfonso Cuarón, returning to his native Mexico after a too-brief stint in Hollywood, where neither of his terrific literary adaptations, A Little Princess and a version of Great Expectations set in contemporary Florida and Manhattan, garnered the attention it deserved. Y Tu Mamá También is an original, written by Cuarón and his brother Carlos, and it appears to have brought this gifted young director finally into the limelight.

To compare this picture to something like Summer of '42 is misleading but instructive, and not only because the sexual content is graphic and gritty rather than muted and romanticized. The two teenage protagonists, Tenoch (Diego Luna) and Julio (Gael García Bernal, of last year's Amores Perros), best buddies who take to the road with Luisa (Maribel Verdú), the runaway wife of Tenoch's cousin, are not, strictly speaking, innocents. Their virginity was lost long ago--perhaps to their steady girl friends (who are off on their own summer vacations), perhaps to other girls. But sexual familiarity hasn't made them men. When they set off with Luisa for a beach paradise that may or may not exist, they identify themselves as members of a juvenile club whose rules they claim to hold sacred. They see this vacation as an adolescent adventure, spiced with beer and marijuana, and with the heady possibility of exotic sex with a married woman on the lam from her unfaithful husband.

What they don't expect is the swirl of darker emotions that boils up when Luisa takes each of them to bed--jealousy, betrayal, and the sudden, bitter taste of mortality. However we choose to characterize their initial condition--in a world where sexual knowledge comes so early, the term "innocence" is at least debatable--it's certain that in the course of Cuarón's movie Julio and Tenoch fall into the Blakean state of experience.