Ennui (2010)

'Ennui' is a slow-burning study of manipulation and control. When Elliott meets his sister's new boyfriend, the charming bohemian Charlie, they strike up an instant friendship. But it is soon revealed that Charlie isn't quite what he seems, as he slowly starts to destroy the relationship between Elliott and his sister Alice; manipulating him into a depraved, drug-fueled life, throwing the lives of those around them into disarray.