Piranesi's house is no ordinary building: its rooms are infinite, its corridors endless, its walls are lined with thousands upon thousands of statues, each one different. Within the labyrinth of halls an ocean is imprisoned; waves thunder up staircases, rooms are flooded in an instant. Piranesi is not afraid; he lives to explore the house. There is one other person in the house - a man called The Other, who visits Piranesi twice a week and asks for help with research into A Great and Secret Knowledge. As Piranesi explores, evidence emerges of another person, and a terrible truth begins to unravel, revealing a world beyond the one Piranesi has always known.