Ethan Hunt is a member of the Impossible Mission Force, an offshoot of the CIA. He and his team go to Prague to stop an American Diplomat named Golitsyn from stealing a list from the American Embassy containing all the covert agents active in Eastern Europe. During the failed mission the entire team as well as the target are killed except for Hunt. Hunt learns that the mission was a set up in order to find a mole in the IMF. The disc with the important list of agents was a fake installed with a tracking device. The head of the IMF, Kittridge, informs Hunt that he believes Hunt is the mole at which point the agent causes a distraction and escapes.
On the run now, Hunt locates the arms dealer, Max, that the mole intended to sell the list to and warns her of the tracking device. Hunt then discovers that his teammate Claire survived their failed mission. He makes plans to meet with Max and offers the real list in exchange for ten thousand dollars. After they agree he narrowly escapes CIA operatives and assembles a new team of disgraced agents. This new team infiltrates the CIA to steal the real list of covert agents and then hides out in a safe house. Hunt finds out his parents have been arrested under false pretenses to draw him out. He calls Kittridge and stays on just long enough for the call to be traced.
Jim, another agent that Hunt thought dead appears and tells him that Kittridge is the mole but Hunt realizes that the mole's actually Jim and another member of the team. Hunt meets up with Max the next day on the train. He hands off the list and Max directs him to the baggage car to find his payment and the true mole. Jim arrives in the baggage car, unhinged, and demands the money. Hunt complies but reveals that he'd secretly recorded the whole thing and sent it to Kittridge, exposing Jim as the mole. A fight between the pair ensues and Jim is killed. With the loose ends tied up Hunt is reinstated but he resigns. He's offered another mission at the end, revealing he'd been undercover the entire time.