It's ironic that this nature-loving naïf is about to shatter her bubble of relative anonymity in a Michael Bay–directed blow-'em-up summer schlockbuster. Lucas plays Alice, a student LaBeouf's Sam Witwicky meets at college. The Internet indicates her character is a Decepticon in human guise, but she's loath to divulge any specifics: "Michael has us all on lockdown. He's supersleuth about every detail." Lucas landed the part after impressing Steven Spielberg with her work in The Pacific, the upcoming World War II mini-series he executive produced with Tom Hanks. Spielberg recommended her to Bay, and she took care of the rest.

Neither Transformers nor her next project, the vampire thriller Daybreakers, seems likely to diminish Lucas' haute-granola spirituality. As we return to the observatory, she digs into her pocket and extracts a tigereye gemstone and a quartz crystal, two good-luck charms she says she carries with her at all times. I interrupt her to ask about a crudely drawn tattoo on her wrist that reads integrity. "Oh, it's not a tattoo," she says. "I wrote that on myself. I do that every day with a word I pull out of a basket my roommate has. Just as a reminder." Perhaps the only thing better than a permanent personal mantra is an ever-changing one, especially for someone as delightfully free-spirited as Lucas. "And sometimes," she confesses sheepishly, "I just write what I need to buy at the store—a grocery list."

Hey, even a hippie girl's got to eat.