He is famous and highly regarded throughout the Culture, a fact that rankles the higher castes of Chel, his estranged homeworld. Quilan, an emissary is despatched to the Orbital, charged with persuading Ziller to return to his own world. But it is made clear that the Chelgrians have concocted this mission to cover a more sinister purpose. Even the emissary himself is unaware of the plot; to evade the potential mindreading abilities of the Culture his memories of the purpose have been erased, and are allowed only to gradually leak back into his mind.