Aggie's life in the village with her aunt is as normal as can be. She has never questioned the rule of the Ministration, or the power of the divine beings - the birds. Then she is sent for by the Master of Murkmere, the great house nearby, who wishes her to be companion to his ward, Leah. Needing the money, Aggie reluctantly leaves her aunt and enters a new life.

But all is not well up at the house. The Master is crippled and unhappy, trapped in a wheelchair, hemmed in with bars, for others' safety, as well as his own. Life is ruled by the steward, Silas, who fascinates and repels Aggie in equal measure. And Leah - the strangest of them all - challenges everything Aggie has ever been taught.