WHEN IT COMES to that particularly British school of realist filmmaking, there's a very fine line that runs between transcendent, grittily effective pathos and boring-ass real life with an extra coat of chip grease smeared across the top. In Fish Tank, the latest from Oscar-winning writer/director Andrea Arnold, this narrow partition is marked with something that looks suspiciously like fishing line—stretched taut, and placed strategically at ankle height.

A familiarly queasy coming-of-age story, Fish Tank follows 15-year-old ruffian Mia (newcomer Katie Jarvis) as she navigates the environmental stumbling blocks of her ne'er-do-well, party-girl mother (Kierston Wareing), the substantial teen girl-boner she's developed for mom's sexy new boyfriend (Michael Fassbender), and—above all else, it seems—the seething anger and resentment that appears to color her every waking breath. But also, obvs, she's got this hella beautiful dream: to be Britain's greatest white B-girl. Then shit gets dark. Shit always gets dark.

As far as British social realism goes, Fish Tank has got quite a lot going for it: The film is beautifully shot and exceptionally acted, and deals with female adolescent sexuality in a subtle, refreshingly frank fashion. And though the film's struggle for uncompromising authenticity is an admirable one, it also turns out to be its greatest flaw. Its narrative is repetitive and predictable, it's curtained in a circuitous and unrelenting sense of dread, there's a constantly looming threat of physical violence, and it's overly long. In other words: just like real life. Realism is one thing, but god knows it's a chore to suffer through most of these misfortunes on a daily basis anyway. Arnold's lens may be unflinching, but it's not particularly insightful. And just as it seems as though the ominous third act might actually redeem the strains of predictability, Fish Tank concludes with an unfortunate you're-gonna-make-it-after-all coda. In spite of its many successes, Fish Tank ultimately falters over a tripwire it's laid for itself.