In the 13th novel, Kōyū is imprisoned under accusation of abusing his powers as Vice Chamberlain of the Department of Civil Administration; because Reishin never did any work, Kōyū had often overstepped his bounds by doing Reishin's work for him. During his imprisonment, Kōyū falls ill from a spell cast upon him by the Hyō clan. When his mother, Yuri-hime, arrives in the capital, she helps him overcome his past memories and how he had devoted his life to trying to please Reishin rather than living for himself and he recovers from his illness. Kōyū is eventually freed; though he loses his position as the Vice-Chamberlain, but he remains an official.