On Inferno the tensions between Spacer and Settler are as strong as ever, but now the majority of robots are working on terraforming rather than as personal servants. Governor Alvar Kresh is content to have his wife give support to the renegade robot leaders she has created, but is not so keen to advertise the fact. Caliban and Prospero, New Law robots, and their fellows have settled in Valhalla, a city in the northern Utopia region. What they are unaware of is that in order to bring the climatic changes essential for further terraforming, the Governora and his political colleagues are planning to bring down the Comet Grieg on Utopia causing massive devastation and creating an artificial sea.