Monster is a true crime movie that tells the story of Aileen Wuornos, a former prostitute who became a serial killer. The film explores her troubled past, her descent into a life of crime, and the murders she committed. It delves into the psychological aspects of her actions and the societal factors that contributed to her transformation. With a powerful performance by Charlize Theron, who won an Academy Award for her portrayal of Wuornos, Monster offers a chilling and thought-provoking look into the mind of a serial killer.