For generations, the Community has thrived within a complex cave system, sheltered from a blight that has infected the rest of the world. Despite the seeming perfection of their society, its people want nothing more than to return to the Outside, and so, every ten years, a Hope is chosen to venture forth and discover whether it is now safe for them to emerge from their rocky home. The Hope has never returned.​

Generations of Fathers and Mothers have always guided the Community, and the people are completely devoted to them and their society, but after Bastion's dad is chosen, he questions whether Father is truly the benevolent leader the rest of the Community believes. His lack of faith leads him on a path of self discovery and redemption, but he loses sight of those closest to him. Through his ignorance he sets the Community on a path that teeters between salvation and redemption.

Sometimes, a little knowledge is a dangerous thing...