A young man, exhausted and delirious, washes up on a beach, looking up momentarily to see two young children (Claire Geare and Magnus Nolan) playing in the sand before he passes out. An armed guard (Tohoru Masamune) discovers him and has him brought to a large, seaside palace where the proprietor, an elderly Japanese man, is told of the stranger's arrival. The only objects found on him were a handgun and a brass top. The old man allows the stranger entry. He is dragged in and given some food which he struggles to eat as the old man picks up the brass top and says, "You remind me of someone...a man I met in a half remembered dream. He was possessed of some radical notions." The stranger looks up in realization as the scene shifts...Dom Cobb (Leonardo DiCaprio) and his partner, Arthur (Joseph Gordon-Levitt), speak to a prospective client, Saito (Ken Watanabe), in an eerily similar dining room about the services they provide; specifically protection against thieves specialized in extracting valuable information from a subject while they're dreaming. Cobb explains that, when one is asleep, one's mind is vulnerable to attack and what he can do is train Saito's mind to subconsciously defend against extractors to protect whatever secrets he may be hiding. He backs up his claim by revealing that he is the most skilled extractor there is and knows all the tricks involved. Appearing skeptical, Saito stands to leave, telling Cobb he will consider his proposition, and exits the room to join a small party in the main hall.Arthur casts Cobb a glance, saying, He knows as the room begins to shake. They walk to an outside balcony where other partygoers mingle and Arthur points to a woman nearby, asking Cobb what she's doing here. Cobb assures him that he'll take care of it and to proceed with the job. He knows where Saito's secrets are; he glanced over at a safe the minute Cobb mentioned the word.Cobb approaches the woman who asks if he misses her. He responds that he does but can't trust her anymore. They retreat to a private room where Cobb ties a rope to the leg of a chair and tosses the end out of the window. He tells the woman, Mal (Marion Cotillard), to take a seat as she asks him if the children miss her. Cobb pauses a moment before saying, "I can't imagine." He then repels out the window to a ledge below, nearly falling when Mal leaves her seat. He breaks into the room below and accesses the safe, swapping out the manila folder inside for another, as the lights in the room turn on. He turns with his gun out to see Mal aiming a gun at him and standing beside Saito and a guard holding Arthur. Cobb asks Saito if 'she told him' as he slides his gun across the table. Saito responds, "That you are here to steal from me, or that we are actually asleep?"This proves true: the three of them are hooked up to a PASIV (Portable Automated Somnacin IntraVenous) device which feeds them the sleep drug Somnacin, keeping them all asleep and allowing dream-sharing. They are watched over by Nash (Lukas Haas), another of Cobb's partners. He checks Saito, sleeping on a bed, before going into another room to check on Arthur and Cobb, both asleep in chairs. Cobb's chair sits above a tub full of water. Explosions and shouts outside get closer as a mob of rioters moves down the street.Inside the dream, Mal holds her gun to Arthur's head but Cobb tells her the threat is empty, as he hands the manila folder over to Saito, since shooting him will only wake him up. Mal smiles in agreement but says that pain is only in the mind and perceived as real as she shoots Arthur in the knee, causing him to cry out. Cobb dives across the table and retrieves his gun before shooting Arthur in the head. He then dashes out of the room under gunfire from Saito's guards.Arthur wakes up and instructs Nash that things are falling apart but Cobb still has time to finish the job before he checks on the still sleeping Saito.Saito frantically opens the manila folder as the dream begins to collapse and shouts in anger as he finds blank pages inside. Cobb manages to hide away for a moment to look at the contents of the real folder which he'd hidden in his jacket, gazing over the confidential files as the building crumbles around him. Saito is crushed by debris and wakes up in the apartment, unseen to Arthur as he reaches under his pillow. Arthur tells Nash to wake Cobb by giving him the kick. Nash pushes Cobb backwards into the tub and, as he hits the water, Cobb's dream is flooded with massive waves cascading through the windows before he wakes up. Saito, having reached under his pillow for his gun, grabs Arthur but is subdued by Cobb who tells him that not all the information he needed was in the file he stole. Saito laughs and claims that all the information he had was in the file because he knew of Cobb's ruse all along. He allowed Cobb and Arthur into his mind as part of an audition which they failed, saying that 'your deception was obvious.'Asserting that his employer, Cobol Engineering, won't accept failure, Cobb throws Saito on the floor and demands that he tell them what they need to know about his expansion project. With his face pressed into the carpet, Saito begins to laugh again and reveals that he is familiar with the material of the carpet; it is supposed to be made of wool instead of polyester. Thus, he comes to the conclusion that he is still sleeping.Sure enough, Saito, Arthur, Nash, and Cobb are all asleep in the car of a train, watched over by a young man named Tadashi (Tai-Li Lee) who monitors the time remaining on the PASIV device. He places headphones over Nash's ears and plays music as a cue that their time is running out. The music plays faintly within the dream but enough that Nash can hear it. As the rioting mob outside draws nearer, Saito commends Cobb on creating a dream within a dream but becomes confused at his inability to control this dream. Nash reveals that they're not in Saito's dream...they're in his. The mob breaks through the door, attacking everyone in the room, and Arthur, Nash, and Cobb wake up on the train. Cobb berates Nash, the architect of the dream, for designing the carpet wrong and throws Tadashi a wad of money before leaving, telling them 'every man for himself'. Saito wakes up moments later to find himself alone in the car, save for Tadashi who's resumed a casual pose, but smiles wryly to himself.