There are a number of things The Runaways does right, and virtually none that it does wrong; yet at the same time, there are very few things it does exceptionally well. Thus it falls into that set of movies that are good, altogether good, and quite perfectly enjoyable for the time that you're watching them, except that I can't shake the niggling feeling that you'd be better off spending your time doing anything else. Such is the ineffable nature, of course, of most biopics.

Compounding matters, the one thing it does absolutely wrong is a pretty dire misstep: it is a movie about the seminal punk girl group that itself fails entirely to be a punk movie. Not that it screws up the details: the Runaways swear and fuck and dress tough and scream their music. But the film itself is quite unassuming and middle-of-the-road, aggressive enough for the people who loved punk in the '70s but are not account executives and upper managers who don't ever watch anything more avant-garde than a CBS sitcom to watch comfortably. Compared to e.g. 24 Hour Party People, which looks at punk and new wave through a raucous stylistic prism, it's more than a little bit disappointing that The Runaways should have so much visually and narratively in common with e.g. Ray. One would expect a veteran music video director like Floria Sigismondi to be a little bit edgier about this, but one would be wrong.

You know the story, even if you don't know the story. In 1975, a teenage guitarist named Joan Larkin, AKA Joan Jett (Kristen Stewart) has the luck to meet a producer, Kim Fowley (Michael Shannon), who responds favorably to her idea for an all-girl rock group. He puts her together with a drummer, Sandy West (Stella Maeve), and then begins the search for a front-woman, a girl who sums up all of Fowley's dreams of sex and youth and anger. They find her in 15-year-old Cherie Currie (Dakota Fanning), whose personal life is not particularly happy - her dad (Brett Cullen) is a drunk, and her mom (Tatum O'Neal) is moving to Indonesia with her new husband - and whose square upbringing very quickly gives way to Fowley's desire that she become, essentially, a jailbait pin-up girl. The band gets big faster than they're ready for, and Cherie gets way in over her head with drugs and fame, and burns out before she can clamber back into being a well-rounded human being.

Ultimately, this is less the tale of The Runaways than it is The E! True Hollywood Story: Cherie Currie (it was primarily based upon her autobiography, Neon Angel, though it was produced by Jett, which may explain the sudden and intense pro-Jett turn it makes in the closing scenes). Which isn't necessarily a problem, though it leaves more than half the band with nothing to do but stand around and fill up wide shots; these roles are played by Scout Taylor-Compton (lead guitarist Lita Ford) and Alia Shawkat (composite bassist "Robin"), both of whom are "name" enough actresses that it's hard to imagine them eagerly taking what amount to cameo roles, and it's possible to imagine that the film we have was cut down from a much more expansive treatment of the band's life with the Cherie Currie material simply being the A-plot. Or maybe Taylor-Compton and Shawkat just wanted some of that Kristen Stewart magic to rub off on them.

Cheap shot! Sorry. Actually, just about the most unexpected and delightfully surprising aspect of The Runaways is its revelation that Stewart can be a perfectly good actress when she sets her mind to it - the same revelation is true of Fanning, but that was more of a "known" prior to now. Admittedly, neither of these young actresses is given many demands by the fairly un-probing screenplay (Stewart especially doesn't have to do much besides get pissed-off, though it's still more than she's done in the Twilight pictures or Adventureland), but they do what they must without fail.

In Fanning's case, this involves a lot of swearing and strutting around in suggestive clothing, and grinding about, and here is where The Runaways perhaps reveals its true colors; it's maybe not so much a story of rock life as it is a vehicle for the young actress to smoke and kiss girls and show off her post-pubescent body in a way that's absolutely less exploitative than it could have been (the Fanning/Stewart kiss is absolutely tame and vague), but certainly leaves the viewer with a queasy feeling: like her character, Fanning was 15 at the time of shooting, and all moral hand-wringing aside, some of what happens could almost qualify as child pornography, given a sufficiently lax definition of pornographic. Not unlike Fowley in reality, Sigismondi doesn't really run from the possibility that all of this is arousing, and well, it's distasteful. There, I'm a prude. Anyway, Fanning has courted such controversy before, which doesn't necessarily mean much here, but at least it's not Shocking! especially because the ad campaign has stressed it so much.

Lost in all this is what ought to be the central question: what does The Runaways say about The Runaways? Not enough: their historical importance is alluded to, but the film doesn't say anything about the music industry or '70s rock that hasn't been said, and it frankly says a lot less than some other treatments on the same topic. Here's what I know from the film: Fowley's exploitation of Currie's sexuality got in the way of the fact that the band had actual legitimate talent, and then Joan Jett started a much more famous and much better band a couple of years later. It mostly reminds me of a less adventurous and non-satiric version of Ladies and Gentlemen, The Fabulous Stains, which had more to say about the commodification of girl power and image control in the music industry 28 years ago than The Runaways is even remotely interested in thinking about.

Parts of it are great: Shannon's portrayal of Fowley as a shallow, slimy genius is right-on (his exclamation, "Jail fucking bait!" is one of the best movie moments of the first quarter of 2010), and anytime the band gets to playing, the movie rises to a whole different level, one that's legitimately dangerous and sexy and raw as hell (Stewart's vocal impersonation of Jett is scarily good, which helps). If the whole movie had stayed in that register, The Runaways could have been one of the great music biopics. But it doesn't, and what we get instead is a modestly diverting film that, at best, might reignite some interest in a good band that broke up over three decades ago.