So like any thespian with a contrarian background, Phoenix chose to pad her résumé in France. She got her first break in Esther Kahn, a film directed by French legend Arnaud Desplechin (My Sex Life). Back home, her wrath in Kahn had art-house mouths spitting gooey adjectives, paving the way for meatier roles in such low-budget staples as Dinner Rush and The Believer—the same career-making formula that worked for Joaquin (To Die For) and River (My Own Private Idaho). After a few more roles, Hollywood took notice of what her surviving brother has long known to be true.

"Summer's really strong," says Joaquin Phoenix. "She has integrity—always has—and takes acting very seriously. She's never wanted to waste time on projects that weren't important to her."

In March, Phoenix takes a swing at the Gen Y masses with a starring role in the heroin comedown Wasted, a made-for-MTV movie. Wasted plays like a mediocre episode of My So-Called Life (jittery quick-cuts, crusty dialogue, and an inescapable nouveau-rocksoundtrack), but Phoenix transcends the trash as a mopey suburban smack addict struggling to get clean—a subject important enough to her to endure working for MTV.

"I don't even watch TV," she says. "But I appreciated the fact that they're trying to be socially conscious."

Now 23, Summer is the same age her brother River was when he suffered his high-profile, drug-induced heart failure outside L.A.'s Viper Room in 1993. For obvious reasons, the subject still isn't easy for her to talk about (she was 14 at the time). But such questions come with her new territory; the cigarette in her slender hand trembles at the mention of his name.

"I mean, there's nothing that I feel I owe the world, any words that are going to wrap anything up for anybody," she whispers determinedly, grinding a tear into her cheek. "He was a beautiful man, a beautiful brother, and I respected him greatly and I miss him so much."

There's a silence, a hard swallow, and then a sliver of a smile burrows its way across her face. "The thing I'll always remember about him," she says, "was that no dream was too big."

In a family of big dreamers, Summer's still got a few plans for her pillow.

"I like to think of myself as the tortoise that wins the race," she says, craning her neck toward the sky. "I'm enduring, ya know?"