A nihilistic murder mystery posing in pretensions and occasional droll droplets of gallows humor, Cory Finley’s Thoroughbreds (C-) neglects consistent character development in the service of a nifty premise. Olivia Cooke is a revelation as a young woman incapable of emotion, and she becomes the perfect partner in crime for a differently depressed rich teen (Anya Taylor-Joy, also good in her role) motivated to slay a wicked stepfather. The men in the film don’t stand a chance, especially Paul Sparks as the diabolical daddy who doesn’t get to do enough evil to justify the trouble. The late Anton Yelchin is charismatic in an underwritten role as a would-be third conspirator. The set-up is elegant, but ultimately the structure crumbles under the women’s feet while they continue to act the hell out of their parts. Like the central character, the film is not funny or absorbing enough to justify getting to know it.