CONTAINS SOME SPOILERS
Confession: it wasn't until after I'd watched (or, more accurately, fidgeted through in an increasingly visible state of annoyance and irritation) this and looked it up afterwards to see if there was any justification for such a colossal waste of an evening, that I found it's not actually a sequel, but a prequel, to Cruel Intentions. It's an origins story that seeks to explore how the hateful, amoral dicks and bitches from Roger Kumble's updating of Les Liaisons Dangereuses (Choderlos De Laclos' original novel is uncredited this time) got that way in the first place, and thus there's no satisfying conclusion.
Douchebag Sebastian (Robin Dunne) transfers to an exclusive New York prep school, sent to live with his dirtbag father who's remarried to a phenomenally wealthy socialite (Mimi Rogers). She has groomed and moulded her daughter Kathryn (Amy Adams!) into a sociopathic ice-bitch with no empathy or feelings for anyone but herself, and events quickly spiral towards all-out war between her and her more laid-back new stepbrother, who has a romantic eye on the headmaster's daughter...
Plot twists that make absolutely no sense, characters who aren't interesting or attractive in their amorality and vicious scheming, and a sour ending in which the bad guys win (albeit one that's setting up the characters for a film that's already been made) make Cruel Intentions 2: Manchester Prep a film that's difficult to like, and the occasional softcore sex scene and the dubiously incestuous flavour to the central relationship (they're step-siblings only by marriage) don't perk things up enough. The cruelty and coldness worked in the first film, but this rehash is one instance where I spent much of the second half shouting abuse at the screen. There's a third entry in the series by other hands that's only slightly connected to these two, and is not currently on my rental queue.