From its opening plop of menstrual blood on Southern California asphalt, The Runaways feints in the direction of being an obstreperously feminist biopic worthy of its subject, the mid-1970s hard-rock band of teenage girls—exploitatively promoted and covered as "real jailbait"—who shattered the sound barrier that kept all-female pop combos in the low-decibel or novelty ghettos. And for much of its first half, veteran music video director Floria Sigismondi's feature debut gives the story a buzzing, underdog energy, transcending the genre's well-worn basics due principally to a pair of nervy impersonations: Kristen Stewart as shag-coiffed, slouching guitar goddess Joan Jett, whose will and ambition can't be denied by a teacher's refusal to let her plug into an amp; and Michael Shannon's often hilarious and ultimately toxic manager-collaborator Kim Fowley, more a glam Beelzebub than Svengali in his studded choker, daubs of face paint, and Nietzschean lack of self-doubt. ("I'm gonna teach you to use your cocks!" is a typical Fowley sneer at his underage protégés in their filthy rehearsal trailer, before he invites some boys in to hurl beer cans at them for "heckler practice.")
Unfortunately, The Runaways isn't really about either of them, or musical alchemy. Hanging out at the same L.A. clubs as Joan is 15-year-old Cherie Currie (saucer-eyed Dakota Fanning, occasionally recalling Patricia Arquette-level catatonia), burdened by a messy home life and scorned with cries of "freak" at her school-assembly lip-sync of Bowie's "Lady Grinning Soul." (Fanning replicates Currie's "underwater" arm-waving brand of solo-dancing impeccably.) Before long, Fowley has recruited Cherie as the front-girl Bardot of the band, browbeating her to drop cooing Peggy Lee-style vocals for a coquettish snarl, imploring her to "sing like you want an orrrrrrrrrrgasm!" Sigismondi paints him as a bottom-line cretin vamping as a visionary, but her script endorses his goals, suggesting that his crass manipulations were the only means of translating the loud-girl-band idea into a major-label career. (The film does give him some creative props when he and Jett appear to improvise the group's signature tune "Cherry Bomb" in about two minutes, like an old MGM bio-musical's scene around a Tin Pan Alley piano. Yet it's a fun moment, not a ludicrous one: "Cherry Bomb" is plausibly a two-minute job.)
The time and place is vivid with a desaturated handsomeness, whether cinematographer Benoît Debie is filling Cherie's wood-paneled family home with harsh, unwelcome sunshine or staging the girls' nocturnal drinking session in the foreground of the floodlit, decaying Hollywood sign. But once the Runaways break through and fragile Cherie becomes a casualty of plentiful drugs and soft-porn photo spreads, Sigismondi's approach (and her adaptation of Currie's autobiography) tacks toward VH1 oh-the-scandal blandness, with generic hotel-lobby collapses, studio meltdowns, and finally a gauzy-lensed reconciliation with Cherie's loyal, loving sister (Riley Keough). Where the movie does stake out new ground is showing Joan and Cherie not only as partners in flushing their contraband down an airplane toilet, but falling into bed together on the road; at least this lack of timidity makes homo-skittish portraits of the '70s like Boogie Nights and Almost Famous look blinkered.
But the plot's focus on Currie rather than Jett is a serious imbalance, particularly given the magnetism gap between the two young actors' characterizations; Fanning's spacey waif can't carry much weight opposite Stewart's persuasive, working-class leather siren, who's capable of both confronting Fowley and teaching her drummer how to masturbate with a showerhead. Finally parted by the incompatibility of Joan's lifer noise-queen chops and Cherie's vulnerability, the two young women could've been the spine of a more daring, unconventional drama, but the film's closing minutes make the whole project primarily seem an origin story for Jett's long-lasting stardom. Its makers fail to connect the nascent musical group's fandom for Suzi Quatro or Ritchie Blackmore to the devotion they inspired in generations that followed them.