Playing a loudmouthed manga warrior goddess might seem like a departure from her usual squeaky-clean, good-girl shtick—but according to her costar Justin Chatwin, it's as close to genuine Rossum as you can get. "Emmy is crazy," says Chatwin, "in the best possible way. She has no internal monologue. There's no barrier between what she says and what she thinks. She can have the maturity of a 4-year-old or the sophistication of a classic movie star."

Back on the boardwalk, Rossum buys us red cherry icees on the way to a little Italian restaurant across Lincoln Boulevard. "This is actually a great place for a first date," she says, looking out at the gulls by the Ferris wheel. "I hate sitting across from a guy and being like, 'So . . . what do you like to do for fun?'" Which, of course, is exactly the scenario we're faced with when we arrive at the café and set our icee cups on the table. Turns out, though, that we share a few passions—Billy Joel's "Vienna," for one ("It's, like, my theme song," she says), and airplanes.

"I love to just stare out the window," she says. "This is going to sound so girly and romantic and awful—but every time I'm on a plane I have this daydream of two people dancing and holding hands and sitting on the clouds. I'm looking out the window and I'm like—" and here she exaggerates a flutter of her eyelashes and says these words: "Deep, long sigh."

Rossum has lived in Los Angeles for only two years, but MTV's Cribs has already found its way to her home near the Hollywood Hills, probing the rows of Ciao Bella gelato in her freezer and the hanging bubble chair by the pool where she writes song lyrics in a little pink diary. Being a homeowner at age 22 has been "kind of scary," she says, presenting a picture that doesn't do much to dispel the sweet-girl stereotype. She's not crazy about the L.A. club scene. She's had the same boyfriend, who works in the music industry, since 2007. She has a garden she tends fastidiously, a grand piano, and—the topper—a little brown Yorkie named Cinnamon and a Chihuahua named Sugar: "Girl dogs," she says (though both pooches are male). There's just one problem: She longs for a little grit.

"I miss New York," she says. "I miss the noise at night. If it's too quiet here I can't sleep. I want one of those noise generators that make beautiful wind chimes—only I want one that makes car alarms." Rossum locks eyes with me and, in a moment of inexplicable synergy, it happens. We duet: "Boooeeep! Boooeeep! Eeek! Eeek! Eeek! Eeek! Boooo-DEEEEE! Boooo-DEEEEE! WEE-you! Wee-you! Wee-you!" Rossum attempts to shift into a story about a plane ride in which the oxygen masks actually dropped—but she stops short. "By the way," she says, "we just did a chorus of New York car-alarm noises. It was kind of amazing."