Hugh Howey starts the book off strong, with an introduction to a hellish earth no longer able to sustain life. Humanity fights to survive in a silo digging deep underground escaping the hellish, toxic conditions in the outside world. In total, the reach a grand total of 144, 1 being the top and 144 being the bottom. In order to monitor the outside world as they stay inside the silo, there are sensors that show the void world of eternal nothingness before them. The sensor stares at a lonely hill in the distance with clouds of dust and toxins separating them. Beyond the hill is a city, which seems to be the only evidence of humans once being able to walk on earth, long abandoned and falling apart. This sensor requires maintenance occasionally clear away the dust and grime that builds up on the lens. The solution is a regulated schedule that sends a person out in a specialized suit only giving them enough time to clean and scrub away the filth and walk away to their death. Holston is currently in this process as he waits in the holding cell before the doors leading outside. Holston is the sheriff, a major figure of authority among three in the silo, the others being the mayor, Jahns, and the deputy, Marnes. Ever since Holston's wife was sent to clean a few years ago after acting strangely from learning classified information, he has been trying to find what she found out. Now, with little hope left, Holston has committed the same crime that his wife, Allison, was sentenced with. Asking to go outside. This is considered the worst crime imaginable in the silo. On the outside, Holston lays his eyes upon a land very different from the depressing, gloomy land shown by the sensors. The ground is green full of vegetation and grass as far as the eye can see, and the sky is blue without a trace of the low hanging dust clouds he has seen all his life. In his glee he remembers to clean the sensor he was sent outside to do. After scrubbing, spraying, wiping, and applying a plastic film for protection, he walks away towards the hill to explore this new world. Halfway up the hill his movements become strained and realizes his suit only supplies the amount of oxygen required for cleaning. He finds a rock and smashes it against his helmet and eventually frees himself. But what he sees is not what he expects. The desolate world returns and he is left there to die.