In 1964, a brash new pro boxer, fresh from his Olympic gold medal victory, explodes on to the scene, Cassius Clay. Bold and outspoken, he cuts an entirely new image for African Americans in sport with his proud public self-confidence with his unapologetic belief that he is the greatest boxer of all time. To his credit, he sets out to prove that with his highly agile and forceful style soon making him a formidable boxer who soon claims the heavyweight championship. His personal life is no less noteworthy with his allegiance to the Nation of Islam, his friendship with the controversial Malcolm X and his abandonment of his slave name in favor of Muhammad Ali stirring up controversy. Yet, at the top of his game, both Ali's personal and professional lives face the ultimate test with the military draft rules are changed, making him eligible for military induction during the Vietnam War.