During the Kyouhou era of the early 18th century, when the thriving merchant culture was evident, Yoshiwara's red-light district in Edo housed a renowned courtesan named Usugumo, admired for her physical beauty and impeccable character. Usugumo is the product of a Christianized prostitute and a shogun named Yoshimune but her status prevents her from being close to her father in the middle of political strife. Everything changes for her when she encounters Kikunosuke, a blonde-haired thief. Along with Kikunosuke, a doctor named Aoto Touichirou, who practices Western medicine, and her feline companion, Kotetsu, Usugumo forms a group of thieves named Kikugumi. But, as they plan daring heists, a member of a mysterious gang appears with their sights set on Usugumo...