Wool and Shift, the first two novels in the trilogy, are fix-up novels (edited-together collections of shorter works); in contrast, Dust was written as a novel. This allows Howey to wrap up the many details of the previous two novels and to structure the third as an intertwining narrative rather than stories featuring recurring characters. Dust is not a stand-alone work; some background context is necessary to understand its plot.

Wool explains the silo world. After Sheriff Holston’s wife, Allison, is condemned to clean the sensors outside the silo—a punishment for those who question silo norms that means certain death—he chooses to join her outside. The world outside the silo seems beautiful and green, but both Holston and Allison die quickly. Holston’s replacement, Juliette, the protagonist of Dust, clashes with Mayor Bernard, the head of IT, the only department in the silo to retain knowledge of the world before the silos. Bernard condemns Juliette to clean, but a reinforced hazmat suit enables her to discover Silo 17. As the first person to survive being outside, Juliette becomes mayor.

Shift explains the origin of the silos.