Fierce People (movie, 2005)

Finn is a teenager trying to escape his drug-addicted mother by going to study tribal people. His hopes are dashed when he gets caught scoring drugs for her, and she decides to start their lives over by moving them in with her massage client, billionaire Ogden. At first, Finn indulges in the luxury around him and falls for Ogden's granddaughter, but he soon finds that the rich can be more savage than any group in the wild.