The book continues shortly after the previous installment left off, skipping Severian's journey from the gate of Nessus to the nearby town of Saltus. Having been separated from the rest of the group he was traveling with, Severian pauses his search for them here as he is given an opportunity to practice his art (in this case, execution) on two people. The first was accused of being a servant of Vodalus, a revolutionary leader. As the man is dragged out of his home by a mob, Severian glimpses Agia amidst the crowd, a woman who with her twin brother had formerly tried to swindle and then kill Severian to gain his valuable executioner's sword. (Severian executed the brother at the request of the local authorities.) Realizing she has been sighted, Agia flees and Severian, still in love with her, follows, searching for her at the town fair. Unable to find her, he ends up at a tent containing a man whose skin is green. The green man is held as a slave, and his master makes money off of him, claiming he can answer any question. In answer to Severian's queries as to how he could know everything, the green man tells Severian he is from the future. The green man does not know where Agia can be found, but Severian takes pity on him and gives him a piece of his whetstone so that he can free himself by grinding through his chains, thus recalling his mercy to Thecla, another prisoner, in the first book. Unable to find Agia, Severian returns to town where he later executes a woman accused of being a witch.