It's often too tempting, and too easy, to evaluate a film against its filmmakers' other output. As valuable as such a process may be, it generally fails to diagnose the merits - or otherwise - of the film itself. In the case of The Unknown Girl, however, it's an unavoidable pursuit. The latest film from the Dardenne brothers is, like all of their output, so very similar to their other films, and yet so crucially different. And those differences emerge not merely in direct comparison, but even in isolation, just as the strengths of their technique yield affecting results in this film as ever before. In short, were The Unknown Girl your first Dardenne experience, you'd still be able to identify its failings. In such comparison, though, they are magnified. One suspects the Dardennes got carried away with what they regarded as the most salient points in their premise, and neglected to address the requirements of their plot. Their unobtrusive style, their dedication to realism - wonderful contributions to cinema, but highly unflattering canvases on which to paint such a shoddy picture. Working with a mystery plot for once not integral to the social study to which this film ultimately amounts, the incongruity of these duelling strains yields questionable results. Attention to detail is flippant and sporadic, coincidence and contrivance make frequent, unnecessary appearances, bizarre narrative ellipses and obscurity muddle important developments. Most damning is the incredibility of Adele Haenel's lead, despite the actor's dogged turn. Her do-gooder doctor is too proficient, too benevolent, too moralistic, dulling the impact of the Dardennes' intended socio-political message. Its ruthless fundaments ensure that The Unknown Girl maintains a driving force nevertheless, and that its purpose is not forgotten even long after it's finished. But the Dardennes have forgotten too much themselves, and my amateur diagnosis is that they've gone off the boil.