In a vertical city called the Stack, space is a luxury and human weight is a liability. Arthur, a man too large for his cramped unit, refuses to be squeezed out by a failing system. When the city’s air filtration fails and the elite abandon the lower sectors to suffocate, Arthur and his brother Silas flee to the forgotten sub-levels. Joining forces with a group of outcasts, they fight back against armored Wardens and industrial decay. Arthur eventually uses his sheer physical strength to break open an ancient ventilation shaft, bypass the city’s filters, and give his people their first breath of the real world.