In the final leg of Phèdre nó Delaunay's journey, vows will be tested and the will of the gods to have a chosen of Kushiel walk the earth will finally revealed. "To damnation and beyond", the vow from long ago, will be pushed to the limit to where not even love will be held sacred. And always, there is a promise made to a friend and an angel to be put back into place. The gods use their chosen hard as the culmination of an anguissette's journey comes to a close.
Melisande and Phèdre make a deal: if Phèdre will promise to find Imriel, Melisande will give her the location of the lost tribe of Dan, whose elders know the Name of the One God, allowing Phèdre to free Hyacinthe of his terrible burden.
Following her own investigations about Imriel from various sources, Phèdre eventually finds out that Imriel had been abducted by slavers along with a couple other Siovalese children. Following their route takes her through Aragonia and Menekhet. In Menekhet she learns that the dangerous bone-priests, the Skotophagoti, from the new born kingdom of Drujan have bought Imriel. These Skotophagoti seem to control death itself and worship an evil god.
This leads Phèdre to Drujan's neighbour and once occupier, Khebbel-im-Akkad. There she learns more of the new kingdom and king of Drujan, the Mahrkagir ("Conqueror of Death"). Each piece of information is more frightening than the last. In Nineveh, Phèdre is refused aid from Khebbel-im-Akkad, despite Valere L'Envers being married to the son of the Khalif, and begins to doubt that she can save Imriel.
When she finally sees Imriel in the zenana, he calls her 'Death's Whore' and spits in her face. In pain and fatigue, she leaves him alone but not without one final message - "I come from your mother, Imriel." She knows that Imriel's curiosity will get the better of his disgust and that he will come to her. True enough, eventually he came and a fragile sort of trust develops between the two.
She eventually comes to learn that in ten days she is to be offered as a sacrifice to the Angra Mainyu, the god who channels power to the Skotophagoti (in Drujan, called the Aka-Magi) by sacrificing a person they love and eating their heart, in an act called the vahmyâcam. The sacrifice symbolizes the destruction of love and a turning away from all that is good. The Mahrkagir has never known love, until Phèdre. By killing her he will become more powerful than before, perhaps also increasing the powers of the Aka-Magi, and can spread his empire across the world. She decides that she must kill the Mahrkagir on the night of the vahmyâcam as they will both be alone, unarmed, and in near darkness. She plots with the women and eunuchs of the zenana as well as Joscelin Verreuil, using Imriel as messenger, to stage an escape.
On the night of the ceremony, during the festivites in the hall, the women of the zenana taint the drinks of all the guards and guests with opium. When taken to the darkened room with the Mahrkagir, Phèdre stabs the Mahrkagir in the heart with a sharpened hair pin. With the Mahrkagir dead, the Aka-Magi loose their powers. In the hall, Joscelin and the women and boys of zenana stage their attack. The slaughter is massive and the cost high but eventually all the drugged guards and guests are killed. Joscelin's arm is badly injured in the fighting and many fighters of the zenana are dead. Phèdre, Joscelin, Imriel, and the rest of the survivors of the zenana flee to Khebbel-im-Akkad.
While Phèdre's skin heals cleanly, the scars on her heart do not, and it takes many months for her and Joscelin to love and understand each other as they once did. After a rhinoceros attack in the camp, Phèdre and Joscelin go to a secluded pool and finally make love, as his caresses erase all of the physical, mental, and emotional scarring that Drujan exacted upon them both. Phèdre and Joscelin soon learn that they have grown to love Imriel as their son and that he has grown to love them like parents.
Phèdre, Joscelin, and Imriel eventually reach the lost tribe of Dan. There the people debate but decide not to let them travel to the island that contains the Name of God. The women, however, disagree with this decision and help Phèdre, Joscelin, and Imriel to escape on boat. They row toward the island of Kapporeth, where the Ark is kept. Having been betrayed, the Sabean male rulership chase after them, leading to a stand-off on the island. The doors then open and Phèdre gains access to the Temple and learns the Name of the One God. She knows that she has been given this covenant so that she may free Hyacinthe from Rahab's curse of the Master of the Straits and should not utter the Name for any other reason or face the One God's wrath.
The tribe of Dan give up their charges as they can see in her eyes that she contains the Name of God. They travel back to Tisaar and on to Meroë with a tentative re-alliance between Saba and Jebe-Barkal. In Jebe-Barkal, Phèdre is given gifts to take back to the Queen of Terre d'Ange and is given gifts of her own. Joscelin receives a traditional warriors outfit, to everyone's chagrin, and Imriel receives a rhinoceros-hide belt to hold his daggers. They travel back the way they came though the journey is very different as it is rushed and Phèdre is acting strangely because she contains the Name of God. She sees beauty everywhere and often forgets to eat or drink, her mind is filled with the Name and sometimes must bite her lips so as to not utter it.
Upon their return to the City of Elua, Phedre throws an enormous party for Hyacinthe's return. Hyacinthe, refusing leadership of the Tsingani, helps choose a new leader for the Tsingani, because he desires to move to Alba to live with Sibeal, Drustan's sister, whom he has come to love.