An air of mystery surrounded Rosamund Pike in "Gone Girl" but there's no mistaking her in "I Care a Lot." Sporting designer suits and a bob cut so sharp that you tremble for her stylist, Pike's Marla Grayson is ruthlessly imperious from head to toe. 

The title of J Blakeson's sleekly sinister neo-noir is tongue and cheek. Marla, a shark on par with Gordon Gekko or Jaws, doesn't care even a little. She's a legal guardian to dozens of elderly people whom she bilks for everything they're worth. A wall of their faces and names adorns her Boston office the way stock portfolios might a financier. "Playing fair is a joke invented by rich people to keep the rest of us poor," she intones in the movie's opening voice over.

When so much  real terror is stalking nursing homes, the timing of "I Care a Lot" (it debuts Friday on Netflix) is perhaps not ideal. Marla's scheme is a particularly loathsome one, and the feeling of disgust only grows as writer-director Blakeson, the British filmmaker of the kidnap thriller "The Disappearance of Alice Creed," depicts an interwoven system of elder abuse, with doctors and nursing home mangers all taking a cut. One of them hands Marla a "cherry" — an especially desirable new ward because she's both wealthy and lacking any apparent living family that might interfere — in Jennifer (Dianne Wiest). A few falsified health records and a judge's rubber stamp later, Jennifer is abruptly hauled off to a facility where her phone is taken and even straying outside is off limits. Marla and her partner-girlfriend (Eiza González), quickly start auctioning off her stuff.

At this point, "I Care a Lot" seems poised to become another nightmare of wrongful institutionalization — a "Shock Corridor" for rest homes. Having Dianne Wiest locked up is no less infuriating than Jack Nicholson being strapped into a mental hospital. But the twists and turns of "I Care a Lot" lead elsewhere — in more comic, off-balanced but generally deviously delightful directions. 

Jennifer turns out to be not just a meek old lady living alone but the mother of a powerful and well-financed underworld figure with ties to the Russian mafia, Roman Lunyov (Peter Dinklage). Dinklage, as he often does, immediately recalibrates the movie, as Roman summons his forces — minions who cower before him while he snacks on an eclair or sips a smoothie — to free his mother. 

It also rebalances our allegiance. There is, in one sense, no one to root for "I Care a Lot," a movie where the most sympathetic figure drugs her imprisoned wards to keep them quiet. Instead, Blakeson's film is gleefully amoral, less concerned with judging its obviously heinous characters than crafting a satire of American capitalism as a system where human trafficking is a mode of doing business. 

It also positions Marla as something more than a greedy vulture. Her resistance to the various entreaties from Roman's team — foremost among them is a very good Chris Messina as a knowing attorney who nevertheless can't match Marla in court — seems reckless and foolish at first. Who would dare turn down a fearsome, well-armed international mafioso who, in this case, also happens to be in the right? But Marla's resistance, as a woman undeterred by male intimidation, accumulates in courage. "Do you know how many times I've been threatened by a man?" she says, utterly unimpressed.

Is this a lot for a film about a corrupt court-appointed guardian? Yes. It doesn't all fit together, and "I Care a Lot" has ultimately no way of resolving its fairly ludicrous plot. But it's strong, gripping, unpredictable pulp, and Pike pulls something off that few else could as a protagonist. She's quite detestable and completely compelling.

"I Care a Lot," a Netflix release, is rated R by the Motion Picture Association of America for language throughout and some violence. Running time: 118 minutes. Three stars out of four.