Pulled away from his vacation, I.M.F. Agent Ethan Hunt (Tom Cruise) is given his latest assignment, where he is assigned to recruit Nyah Hall (Thandie Newton), a beautiful thief, and require her skills. After recruiting Nyah, Ethan's boss, Mission Commander Swanbeck (Sir Anthony Hopkins) gives Ethan the assignment. Renegade I.M.F. Agent Sean Ambrose (Dougray Scott) has killed an old friend of Ethan's, Russian scientist Dr. Nekhorvich (Rade Serbedzija), and has stolen "Chimera", an engineered virus, and "Bellerophon", the cure, which Dr. Nekhorvich created and was carrying to Atlanta, Georgia, while accompanied by Sean, who was disguised as Ethan. Ethan learns Nyah was Sean's former lover and has been recruited to help Ethan track down Sean. After tracking down Sean, Ethan, Nyah, old friend and fellow I.M.F. Agent, computer expert Luthor Stickell (Ving Rhames) and Australian helicopter pilot Billy Biard (John Polson) arrive in Sydney, Australia. Where Ethan's mission is to destroy the "Chimera" virus and recover the "Bellerophon" cure, and stop Sean and a group of international terrorists from unleashing the "Chimera" virus and infecting the whole world, and save Nyah, who has been infected and find the cure, before she dies a terrible death.