Dom Cobb is an "extractor" — a specialist who enters people's dreams to steal ideas from the subconscious. He is offered a different assignment: inception — not extracting an idea but planting one, making the target believe the planted idea is his own. The target is Robert Fischer, the heir to an energy empire. The idea to be planted: that he should dissolve his father's company. The team assembles, the dream levels are designed, and the operation descends through three layers of Fischer's subconscious — each layer a dream within a dream within a dream, each with its own architecture, its own dangers, and its own time dilation.
But the film's actual subject is not Fischer. It is Cobb — and his inability to distinguish between the dream world and reality because of his grief for his dead wife Mal, who haunts every dream level as a projection of his own guilt and refused mourning. The heist plot is the surface. The real film is about a man trapped in his own mind, unable to return to his children because he cannot let go of the dead, and the inception that finally frees him is not the one performed on Fischer.