Kushiel's Mercy is the third and final book in the Imriel trilogy. It begins with Imriel returning from Alba with Sidonie after burying Berlik's head at the foot of Dorelei's grave. Both Imriel and Sidonie have to deal with the consternation and suspicions that their relationship causes. Ysandre tells Imriel that if he brings Melisande to justice then she will give her blessing to his and Sidonie's union. Before Imriel can do this thing, though, the city is brought under a terrible spell and Imriel must travel far to save Terre D'Ange and all that he knows and loves.