Mía Maestro savors Manhattan. The city reminds her a bit of Buenos Aires—or rather, the Buenos Aires of her childhood. Before the economic crash. Before the kidnappings. Back when it was safe to hail a cab. "It's like a little Colombia now," she says, closing her eyes. Maestro's beauty is so understated, even the hulking watch on her wrist seems demure.

The actress, 26, is looking for a place in New York but grudgingly accepts that the life of an ingenue is in Los Angeles. So she rents a West Hollywood apartment with her boyfriend of two years, a screenwriter and playwright she met in Italy. She likes to drive—she bought a Mini Cooper S, stick shift, gray—but nothing compares to the rush of a Harley. It's not surprising, then, that she felt right at home on the set of The Motorcycle Diaries, director Walter Salles' love letter to Ché Guevara, which opens this month. Maestro stars as the would-be revolutionary's girlfriend, the silver-spoon-fed Chichina, whom he leaves in favor of a buddy road trip and a three-week stint at a leper colony. (Had El Ché not been destined for greater things, this plot point would have been highly improbable.)

Chichina and Guevara, played by Y Tu Mamá También's Gael García Bernal, paw each other in the back seat of a 1952 Buick, she begging him to stay, he begging her to take off her pants. Their chemistry is—¿cómo se dice?—atomic. "I had the impression that both Mía and Gael were not acting the scene but living through it," says Salles. "I could see that we were reaching something delicate and special."

"Mía is quite capable of being a superstar," says Mike Figgis, who directed her in Timecode and Hotel. "But I cannot imagine a diet of middle-of-the-road studio pictures being quite satisfying for her." And Maestro admits as much. She nearly snagged the lead in Daredevil opposite Affleck and seems almost relieved not to have gotten the part. (She has a recurring job on Alias to pay the bills.) She still works in Latin America. She's considering doing a musical next year in Copenhagen. And she may record an album. Something jazz, perhaps. But don't compare her to another fetching Latin crossover: "I'm not Mía from the block," she says.