The Arbiter (2013)

John (35) is a bright Cambridge scientist, who always comes across as a pleasant fellow. When his fiancée leaves him, he withdraws from his world of academic isolation in order to try out some of his long-gestating theories on how to make the world a better place. On his journey through the English countryside, John is accompanied by his 14-year-old donor child - Ronja, whom he tries to convert to the same radical ideas that he believes in. Murder. Elimination. Cleansing. All justifiable in the mind of a modern day European Psycho.