People are awful and capitalism has created a world in which the vulnerable can be exploited for cash. That’s the primary message of J Blakeson’s I Care A Lot. It’s a warning and a lesson, to be sure. It is, however, surprisingly, quite a lot of fun. This blackest-of-the-black satirical thriller ticks along like a meticulously planned heist movie, and while it’s difficult to root for absolutely any of these abhorrent characters, there’s still a perverse pleasure in watching their well-executed plans (and well-planned executions) take shape and pay off.

The dark heart of the movie is Rosamund Pike’s Marla, a “professional guardian” onto an ingenious but completely horrible scam: she gets a doctor to declare elderly patients unfit to take care of themselves, has the court name her their legal guardian, packs them off to be dosed-up in a care home (removing their phones, mobility and basic human rights in the process) and flogs off their assets to pay herself a hefty salary. It’s clever and hideously plausible.

It’s all going like a dream, until she targets Jennifer Peterson (Dianne Wiest), apparently a “cherry”, a perfect mark with no family or contacts and a lovely-looking house. Jennifer, however, has some skeletons in her closet, alongside a few million dollars worth of diamonds and a son (Peter Dinklage) high up in the Russian Mafia. Wiest is brilliant, pitching the genuine shock and then angry bewilderment of her official abduction by the state perfectly, and then layering in a hint of slurred menace as Pike’s Marla starts to sense things are slipping. Dinklage, too, makes the most his role as powerful Mafioso Raven. The same blue-eyed stare that radiated sympathy and hidden pain in Game of Thrones is turned steely and blank. It’s a superb performance, (even if his facial hair seems to be modelled on Twitter CEO Jack Dorsey’s recent US Senate appearance.)

This is Pike’s film though, and she earns every award nomination this is going to bring her. It’s a masterclass in playing high-status; just as scheming as she was as Amy in Gone Girl, with even more sociopathic mind games. We are genuinely convinced that she is bulletproof; dead-eyed, razor-bobbed, unflappably determined and motivated only by a desire to be “really fucking rich”.

There’s a moral dilemma here, because Marla’s scheme, let’s make no bones about it, is absolutely horrible. She targets the most vulnerable, entirely out of self-interest, and everyone along the way, from the corruptable doctor to the greedy care-home staff, is in on the scam. The film puts a layer of gloss on a practice that is genuinely happening, right now, as you read this. We should hate Marla. We should hate her so much. And yet spending time with her is not the chore you might think. Blakeson keeps us more-or-less on her side as she becomes a piranha swimming among sharks.

We might not like her, but we’re certainly impressed and engaged by her determination and cleverness. There’s an argument to be made that this isn’t an entirely healthy thing, that the film should feel more scabrous, dirtier, bleaker. That we should be less invested in Marla and more focussed on her victims. The film never actually approves of its awful business, but it’s only briefly, in Dianne Wiest’s haunted expression, that we really feel the reality of its exploitation. Blakeson and Pike are just that little bit too good at, well, looking good. It’s a very stylish film. I’m not sure that’s for the best.

Still, whether you approve or not, it’s a breezy and entertaining watch, powered by an excellent eye and three more-than-solid performances, which apparently sweeten the pill enough to mask the bad taste it should leave in your mouth.