Slickly produced and assembled, Before I Go to Sleep is an effective woman-against-the-world thriller (or woman-against-the-world-she-knows), though one that reveals itself to be rather less than it has promised. The hook is strong - an amnesiac attempting to unravel the mystery of her current condition, fighting the clock day after day - but its strength diminishes as that mystery comes into clearer focus. Following Nicole Kidman's Christine, what becomes clarity for her merely seems like a passable explanation for us, and the disorientating jumble of conflicting information that makes the film so involving, albeit in spurts, is revealed to be quite a simple story, simply rearranged to induce our paranoia. Rowan Joffe proves adept at doing just that, though. And while Before I Go to Sleep's lasting impact may be dampened by the plot's broken promise of ingenuity and inspiration, these characters don't actually need any additional complexity to justify their purpose. Instead of portraying its female lead as a vulnerable victim, Before's Christine is a figure of immense determination, whose relationships are based not on foolish trust but on reasonable mistrust. She's a victim only of circumstance, and the smart ploy of frequently insinuating a Machiavellian treachery in all of Christine's male acquaintances, whether they warrant it or not, serves as a satisfying feminist gesture. Unfortunately, thrillers like this can't thrive on subtextual depth alone, and Joffe's handle on the technical side of his film is disappointingly slack. The pace is run into the ground every time he stops to half-assedly indulge in emotional subplots that have no potential for organic growth, and if tricking the audience with misinformation is acceptable, given the mentality of his protagonist, his crude and obvious manner of drip-feeding us supposed clues relating to the truth only makes the eventual pay-off even more underwhelming.