From Wikipedia

Kushiel's Mercy is the final novel in Kushiel's Legacy by Jacqueline Carey. It is the sequel to Kushiel's Justice. Kushiel's Justice follows Kushiel's Scion, which makes Kushiel's Mercy the sixth book in the series, or the third book in the series dubbed the Imriel Trilogy. Read more - Shopping-Enabled Wikipedia on Amazon

In the article: What Came Before | Plot summary

From Publishers Weekly

In this vivid conclusion to the second Kushiel trilogy (after 2007's Kushiel's Justice), young Prince Imriel and his beloved, Sidonie, heir to the Terre D'Ange throne, struggle to come to terms with the deaths of Imriel's wife and unborn son. Queen Ysandre threatens to forbid Imriel's marriage to Sidonie unless he hunts down his traitorous mother, Melisande. Then a spell convinces everyone in Terre D'Ange's capital that Sidonie loves the prince of Carthage, and she sails off to wed him. Only Imriel remembers their romance. He must evade deluded loved ones and work with erstwhile enemies to rescue Sidonie and pull the country back from the brink of war. Carey delivers a heady mix of adventure, power struggles and romance, but fans of the first Kushiel trilogy may be disappointed by the few appearances of Phèdre, Imriel's adoptive mother, and by the relatively tame sexuality, which serves more as a spice than a larger theme. (June)
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