Plot
Dominic "Dom" Cobb (Leonardo DiCaprio) washes up on a beach and is brought by armed guards into the chamber of an elderly man. The scene then cuts to a dream in the mind of Saito (Ken Watanabe) where Cobb, Arthur (Joseph Gordon-Levitt) and dream world architect Nash (Lukas Haas) are on an "extraction" mission, in which an individual's mind is infiltrated through dreams and information is stolen. Extractors and their victims sleep in close proximity to one another, connected by a device that administers a sedative and share a dream world built on their mental projections. In the dreamworld, pain is psychologically experienced as real but death results in awakening. Cobb carries a spinning top to use as a "totem", a unique object which either spins unceasingly or topples, allowing him to always determine whether he is dreaming or awake, respectively. Unbeknown to Cobb or Arthur, Saito is in fact auditioning the team to work for him.
Saito asks Cobb to perform the act of "inception"; using dreams to secretly implant an idea. The target is Robert Fischer (Cillian Murphy), son of Saito's terminally ill corporate rival Maurice Fischer (Pete Postlethwaite). The objective is to convince Fischer to break up his father's company, preventing it becoming a monopoly, forcing Saito out of business. Cobb recruits Eames (Tom Hardy), a forger who shifts identities inside dreams, Yusuf (Dileep Rao), a chemist who develops sedatives and dream architect Ariadne (Ellen Page). In Cobb's mind, Ariadne discovers that a vision of his deceased wife Mal (Marion Cotillard) continually haunts him, constantly sabotaging his missions. Cobb reveals to Ariadne that he and Mal spent many years in a limbo dream world forging their lives. After waking, Mal remained convinced that she was still in a dream and committed suicide, attempting to force Cobb to join her by incriminating him in her death. Cobb refused, forced to flee the U.S. and his children to avoid murder charges. In return for the mission, Saito promises to clear the charges and reunite Cobb with his children. The plan involves creating three dream layers—essentially, a dream-within-a-dream-within-a-dream—and due to the strength of Yusuf's sedative, death will not awaken a dreamer, but instead send them into limbo, leaving their real body comatose for an indeterminable amount of time. At such a dream depth, the duration of the plane's flight would be the equivalent of fifty years stranded in limbo.
When the elder Fischer dies in Sydney, Saito and Cobb's team share the flight with Robert Fischer back to Los Angeles and drug him. They first enter into Yusuf's dream, a rainy inner city area, and kidnap Fischer. The team are fired upon by security forces, which represents by Fischer's trained subconscious defenses, and Saito is badly injured. Eames takes the identity of Peter Browning (Tom Berenger), Fischer's godfather, to try and extract information from him. The team then enters a van and sleep into the next dream level, hosted by Arthur; a hotel where the team tricks Fischer into believing that the kidnapping on the first level was orchestrated by Browning. Cobb convinces Fischer to enter Browning’s subconscious in order to find out his motives, but in fact the team enter deeper into Fischer's. The third level is Eames' dream, a snowy mountain fortress, which Fischer must break into to reveal the planted idea. Fischer is killed by Mal, causing Fischer to go into limbo. Ariadne comes up with the unprecedented idea that she and Cobb should follow Fischer to this fourth level in an attempt to salvage the mission and confront Mal. Back when they were in limbo together, Cobb planted the idea in Mal's mind that her life was not real in an attempt to wake her up, and is indirectly responsible for her suicide. The guilt he feels is what causes Mal to sabotage all of his missions. Mal attempts to convince Cobb to stay in limbo and attacks him, but Ariadne shoots her. Fischer and Ariadne are able to return to the mountain fortress, where he reaches the intended understanding that his father had wanted him to be his own man.
To successfully return to reality, a team member is left behind on each dream level: Yusuf driving the van, Arthur in the hotel, and Eames and Saito in the fortress, to protect those in the next level and fight off Fischer's security forces keeping them from attacking the bodies. Ultimately they are running out of time, since at each level, timed "kicks" to help them return to reality are imminent: the mountain fortress falling due to the explosives, the elevator hitting the end of the shaft in the hotel, and the crashing of the van into a river. A wounded Saito dies slowly at the snow fortress and Cobb remains in limbo to locate him. Returning to the first scene in which Cobb locates an aged man—now revealed to be Saito—and tells him that they need to escape back to reality. Cobb suddenly awakens to find everyone on the plane, including Saito, awake and well. Saito honors their arrangement and Cobb enters the United States, reunited with his children at home. Cobb spins the top to test reality, but is distracted by the joyous reunion with his children. The top begins to wobble, but the scene cuts to black before it can either fall or remain spinning, which leaves the question of whether Cobb is awake or still dreaming.
Starring
Leonardo DiCaprio
Ken Watanabe
Joseph Gordon-Levitt
Marion Cotillard
Ellen Page
Tom Hardy
Cillian Murphy
Dileep Rao
Tom Berenger
Michael Caine
