Poised with sharklike self-assurance, Marla Grayson (Rosamund Pike) is a professional, court-appointed guardian for dozens of elderly wards whose assets she seizes and cunningly bilks through dubious but legal means. It's a well-oiled racket that Marla and her business-partner and lover Fran (Eiza González) use with brutal efficiency on their latest "cherry," Jennifer Peterson (Dianne Wiest) - a wealthy retiree with no living heirs or family. But when their mark turns out to have an equally shady secret of her own and connections to a volatile gangster (Peter Dinklage), Marla is forced to level up in a game only predators can play - one that's neither fair, nor square.