Lily (Anya Taylor-Joy) and Amanda (Olivia Cooke) are friends who have grown apart but find themselves coming back together in the new movie Thoroughbreds. Neither is particularly happy in their suburban Connecticut lives and are often a source of frustration to their parents and family. Lily is upper-crust while Amanda is a social misfit. One thing they have in common is their hatred of Mark (Paul Sparks), Lily’s stepfather.
With a shared goal in mind, the pair begin to consider the possibility of murdering him to rid the world of an odious human being. The idea becomes more and more concrete until they reach out to a small-time local hood named Tim (Anton Yelchin, in his final role) for help. That’s on the beginning, though, as their newfound sociopathy only escalates thanks to the self-reinforcing nature of Lily and Amanda’s friendship.