Okō and Seiji own and run the Izumo-ya lending shop in the Fukagawa district of Edo.

Seiji is clever and, with the help of the tsukumogami, has a reputation for being able to solve mysteries and other difficult problems.

One of those mysteries is the whereabouts of Satarō, a man who was once interested in Okō despite being engaged to another woman.

The novel is written by Megumi Hatakenaka, and Kadokawa Shoten published it on September 25, 2007 (ISBN 978-4-04-873786-9).

[1] Anime Limited acquired the series for distribution in the United Kingdom and Ireland.