Dramatic biography of boxing great Muhammad Ali, which focuses on the ten-year period of 1964-1974. In that time, the brash, motor-mouthed athlete quickly dominates his sport, meets and marries his first wife, converts to Islam (changing his name from Cassius Clay), and defies the United States government by refusing to submit to military conscription for duty in Vietnam. His world heavyweight champion title thus stripped from him entirely for political reasons, the champ sets about to win back his crown, culminating in a legendary unification bout against George Foreman in Zaire, dubbed the "Rumble in the Jungle."