The fifth volume of The Book of the New Sun. The Urth of the New Sun mostly takes place outside Urth. The book continues Severian's narration of the aftermath of his ascent to the throne and subsequent journey between the suns to be judged and win back the fountain of life that will rejuvenate the slowly dying sun and revive life on Urth. When the book begins, Severian has already rewritten his accounts of before and is beginning his new log aboard the spaceship that will take him to Yesod, an enigmatic planet, home to the godlike beings who have the power to grant Urth and its sun a new lease on life.