Dominic Cobb was an extractor and architect of dreams who was one of the most skilled in the business.
Together with his wife Mal, who he met at university, Cobb explored dream sharing and extraction of ideas from dreams. During their experiments, the two ended up venturing to deep into the dream world and found themselves in Limbo, the unconstructed dream space. They stayed to explore, and built themselves a vast city out of their imaginations. While Dom always maintained the fact they were dreaming, Mal began to get lost in the world they had created and soon would not accept that their world was not real. So Dom performed inception on her, planting the idea in her mind that her world was not real. He convinced her to wake herself up by laying down together on a train track and committing suicide.
The pair woke up in the real world, but Mal still held the notion that her world was not real, and tried to convince Dom to commit suicide with her to wake up again. He would not do it, but she set up a situation at a hotel room where if he did not jump out of the window with her he would be frame for her murder and never again see their children, Phillipa and James. He refused to jump, and watched her fall to her death. He then fled America and made a living as a professional thief of ideas from people's minds.
Together with Arthur, Nash and Tadashi, Cobb agreed to a job for Cobol Enterprises to steal an idea from the mind of their rival, Mr Saito. On a train in Japan, they put Saito under for two levels of dreaming and stole the secret from a safe in a japanese fortress dream. However, a projection of Dom's dead wife gave them up to Saito, and he was forced to flee. In the next level up, Arthur woke Dom and Saito from their dream by tipping them into a bath. However Saito quickly realised he was still dreaming due to the texture of the carpet, and the operation was aborted. Arthur and Cobb fled the train and went to a hotel.
cobb the extractor
Cobb phoned his children before leaving Japan, promising to see them again soon. He and Arthur went to the hotel roof for their waiting helicopter, but found that Nash had betrayed them to Saito. Saito proposed a job for Cobb - he was to perform inception on Robert Fischer, who was to inherit the empire of Maurice Fischer, Saito's main rival. Cobb agreed to it, and travelled to Paris to find a new architect.
In Paris Cobb visited his old teacher Stephen Miles. He asked for a pupil of Miles, and he brought Ariadne. Cobb began to teach Ariadne all about the skills of dream sharing and architecture. Cobb then travelled to Mombasa to visit his old friend Eames, who told him that inception was possible. Dom was chased by two businessmen from Cobol Enterprises, but was rescued by Saito who was keeping an eye on him. Saito told him more about the target, and Cobb then visited a chemist called Yusuf who he put in charge of sedation, as he needed 3 levels of dream for the job. Saito then informed Cobb that he wanted to come on the job too.
Shortly before the job, Cobb dreamt memories of his wife, and Ariadne entered the dream as well. She insisted on coming on the job, because of the danger of his wife as a projection. He agreed, and the team then boarded a 747 with Fischer. They were all sedated, and entered the first level of the dream. They captured Fischer on a New York street, but had to contend with Fischer's militarised projections, and Saito was shot. Cobb became angry at Arthur for not being prepared, and then revealed to the team that the sedation they were under meant if they die they would drop into Limbo.
Cobb then start to tell Ariadne more about what happened with his wife. Eames then disguised himself as Peter Browning and questioned Fischer. They all entered a van and were put to sleep again, to the second level of the dream. Cobb introduced himself to Fischer in a hotel bar, calling himself Mr Charles. He explained that people were trying to invade Fischer's mind; more precisely Dom is trying to make Fischer think Peter Browning then used that projection Robert made of Peter that he had arranged their kidnapping and invading his mind. From all that matter was to convinced Robert the best course of action was to dream share with Cobb into Peter's mind which was actually a lie as well. The team all entered a hotel room and were put under, to the third level, the mountain hospital.
Cobb and Ariadne skied through the mountain and set up position watching the hospital. However, just as Fischer was about to enter the door, Cobb's projection of Mal appeared and shot Fischer. Cobb rushed down, just in time to see Fischer die. He and Ariadne then dreamt one level deeper, and ended up in the city that Cobb built with Mal. They located Fischer, but Mal was waiting and asked Cobb to stay. He told Ariadne to take Fischer and jump out of the window to kick themselves back to the next level - but he remained, in order to find a closure between him and Mal, to seek out for Saito and to ensure his safe passage into America.
He searched Limbo, eventually being washed up on a beach and taken to Saito. He reminded him of his past life, and the two committed suicide together and jolted themselves out of the dream. They woke up back on the 747, and Fischer decided to break up his father's empire as required. Cobb was then allowed into America, and met Miles off the plane. He was taken to his children, but just before running out to greet them he spun his totem to see if he was dreaming. Before the totem stopped spinning, he turned away from it and ran out to his waiting children. However, the scene remains unclear about whether the totem would stop for sure as it was cut abruptly while the totem were starting to shake. Thus, the ending might deliberately end more like a cliffhanger for audience to imagine or interpret into varieties of ending.