That's just one of the many times that Brian Nelson's clever script upends our expectations. As soon as we think we know all there is to know about Hayley and Jeff, Nelson hits us with some more information, right up until the last scene. But however much we learn about the duo, we don't learn much about the wider issues which the film touches on.
With its crafty twists and its arch verbal sparring, Hard Candy would be ideal as a single-act fringe play, but as a full-length film it isn't illuminating or even provocative. No one's going to leave the cinema having to rethink their position on either paedophilia or torture.
What's particularly dubious is that the scratchy-voiced Hayley is as much of an ass-kicking fantasy figure as any computer game heroine. If a film's going to take on such grave subject matter, and plead that children should never be mistaken for adults, however mature they might seem, it shouldn't make its 14-year-old lead a super-articulate criminal mastermind - quite apart from the damage it does to the plot's credibility. Either Hayley has a godlike ability to improvise the perfect comeback and the perfect plan in any situation, or else someone's given her a sneak preview of the screenplay.
Hard Candy is an unpleasant film - not just because any film in which a child-abuser (perhaps) is chopped open (perhaps) by a teenager would be less than pleasant, but because of the self-satisfied way it handles this lurid scenario. It's a slickly sadistic horror film that pretends to be experimental by putting a blue filter on the camera. It might look hard, but, really, it's just candy.