There might be something inauthentic about, say, a teenage blues band, but post-pubescence is the prime age for proper rock. As one character in the rock biopic "The Runaways" remarks, "That's the sound of raging hormones!"

There might be something inauthentic about, say, a teenage blues band, but post-pubescence is the prime age for proper rock. As one character in the rock biopic "The Runaways" remarks, "That's the sound of raging hormones!"

The film runs in familiar rise-and-fall rock territory, telling the tale of the '70s all-girl rock band that melded raw talent and snarl with calculated jailbait titillation.

It centers around the converging paths of Joan Jett (Kristen Stewart), a SoCal teen rocking black leather and inhalants, and Cherie Currie (Dakota Fanning), a pretty blond misfit trying to channel David Bowie.

The pair is united by Kim Fowley (Michael Shannon), a rock producer who's as exploitative as he is pragmatic. He's the drill sergeant at rock 'n' roll boot camp, forming his band and sending them to the front lines of an international tour.

The first thing "Runaways" gets right is the tone. Director Floria Sigismondi - working from Currie's autobiography - sets up an angsty first act that should feel familiar to a lot of teens, regardless of gender or generation. And it makes the rock-star fantasy that follows feel like our own.

Stewart is a fine Jett, full of attitude, pain and shocking confidence. Fanning stretches way beyond her child-star roots, overreaching just a bit into Jim Morrison territory. Shannon is a snarling animal and the best reason to see the film.

Like youth, "Runaways" hits an awkward phase. It stumbles across the finish line, but it starts strong enough to give it a shot.