Retired IMF agent Ethan Hunt gets thrown back into the mix when his protégé Agent Lindsey Farris gets captured in Berlin by Owen Davian, a prominent dealer in the international black market. After his failure to save her, Ethan decides to go after Davian himself. But this causes the kidnapping of Ethan's wife Julia, forcing him to jump through hoops for Davian, as he tries to find her before Davian has her killed.
Fellow IMF agent Luther Stickell returns from the first two movies.
Ethan Hunt has retired from field work for the Impossible Missions Force and instead trains recruits while settling down with his fiancée, Julia Meade, a nurse who is unaware of Ethan's true job. Ethan is approached by fellow IMF agent John Musgrave about a mission to rescue one of Ethan's protégés, Lindsey Farris, who was captured while investigating arms dealer Owen Davian. Musgrave has already prepared a team for Ethan: Declan Gormley, Zhen Lei, and his old partner Luther Stickell, who are waiting in Berlin.
The team rescues Lindsey and collects two damaged laptop computers. As they flee via helicopter, Ethan discovers an explosive pellet implanted in Lindsey's head. Before he can disable it, it goes off and kills her. Back in the U.S., Ethan and Musgrave are reprimanded by IMF Director Theodore Brassel. Ethan learns that Lindsey mailed him a postcard before her capture and discovers a magnetic microdot under the stamp.
IMF technician Benji Dunn recovers enough data from the laptops to determine Davian will be in Vatican City to obtain a mysterious object called the "Rabbit's Foot". Ethan plans a mission to capture Davian without seeking official approval. Before leaving, he and Julia have an impromptu wedding at the hospital's chapel. The team successfully infiltrates Vatican City and captures Davian.
On the flight back to the U.S., Davian threatens to kill Ethan and his loved ones. Ethan then threatens to drop Davian out of the plane, during which Davian overhears Luther calling Ethan by his first name. After landing, Ethan learns that the microdot contains a video of Lindsey warning that she believes Brassel is working with Davian. The convoy taking Davian across the Chesapeake Bay Bridge–Tunnel is suddenly attacked, and Davian escapes. Fearing for Julia's safety, Ethan races to the hospital, only to find she has already been taken. Davian gives Ethan 48 hours to recover the Rabbit's Foot in exchange for Julia's life, but Ethan is soon captured by the IMF.
Musgrave takes part in Ethan's interrogation but discreetly mouths that the Rabbit's Foot is located in Shanghai, China, and provides Ethan with the means to escape. Ethan and his team raid the building where the Rabbit's Foot is secured, and inform Davian that they have the Rabbit's Foot. Ethan, delivering the Rabbit's Foot alone, is forced to take a tranquilizer. As he comes to, he realizes a micro-explosive is implanted in his head. The restrained Ethan sees Davian apparently holding Julia at gunpoint (the full scene opens the movie). Despite Ethan asserting that he brought the real Rabbit's Foot, Davian shoots Julia and leaves.
Musgrave arrives and explains that the woman killed by Davian was not Julia, but Davian's translator in a mask, executed for failing to protect Davian in Vatican City. The Julia-mask was used to force Ethan to confirm the authenticity of the Rabbit's Foot. The real Julia is alive and held as Davian's hostage. Musgrave reveals himself as the mole, having arranged for Davian to acquire the Rabbit's Foot to sell to a terrorist group so the IMF would have reason to launch a preemptive strike. Musgrave asks Ethan about the microdot Lindsey sent, wanting to know if Lindsay had compromised him. To convince Ethan to cooperate, Musgrave dials his phone for Ethan to hear Julia's voice to confirm she is alive. Ethan bites on Musgrave's hand and knocks him unconscious, freeing himself, and uses Musgrave's phone (with Benji's help) to track down the location of Musgrave's last call. Ethan finds Davian and pushes him into the path of a truck, but not before Davian triggers the countdown of the micro-explosive. Freeing Julia, Ethan instructs her to electrocute him, deactivate the explosive, and then revive him. He also instructs her in using a gun for her protection. While reviving Ethan, Julia fatally shoots Musgrave. She successfully revives Ethan, and he explains his true IMF career to her.
Back in the U.S., Brassel congratulates Ethan as he leaves for his honeymoon with Julia. Ethan is unsure if he will return to the IMF. Brassel promises that he will tell Ethan what the Rabbit's Foot is if Ethan will promise to return. Ethan smiles and walks off with Julia.
- Tom Cruise as Ethan Hunt
- Ving Rhames as Luther Stickell
- Philip Seymour Hoffman as Owen Davian
- Simon Pegg as Benji Dunn
- Michelle Monaghan as Julia Meade
- Billy Crudup as John Musgrave
- Keri Russell as Lindsey Farris
- Maggie Q as Zhen Lei
- Jonathan Rhys Meyers as Declan Gormley
- Laurence Fishburne as Theodore Brassel
- Bahar Soomekh as Davian's Translator
- José Zuniga as Pete
- Sasha Alexander as Melissa Meade
- Aaron Paul as Rick Meade
- Eddie Marsan as Brownway
- Michael Berry as Kimbrough
- Tracy Middendorf as Ashley
- Rose Rollins as Ellie
- Greg Grunberg as Kevin
- Carla Gallo as Beth
- Paul Keeley as Ken
- Bellamy Young as Rachael
- Sabra Williams as Annie