Kiyo is a lady-in-waiting who serves the Asano family’s Edo mansion in the Genroku Period. She has fallen in love with Isogai Jurozaiemon, a samurai of the Ako domain. Kiyo sets her mind to overcome the difference in social status and live for love. But at that moment, bloodshed occurs when Asano Naganori, the young lord of the Ako domain, attacks the master of ceremonies, Kira Yoshinaka, inside Edo Castle. This incident sets Kiyo’s destiny in motion as the 48th “loyal vassal” unable to participate in the raid with Jurozaemon and the rest of the 47 lordless Ako samurai. After they pull off the raid on Kira’s residence, Kiyo’s second life begins. She gets close to a family positioned to accede to the shogunate and eventually enters the inner palace of Edo Castle with the aim of restoring the Asano family.

Set in the Edo period, a story revolves around Kiyo, a woman who strives to overcome status differences of those days. When she pledges to live for love, a knife attack occurs at Edo castle. And as a 48th loyal retainer, her fate changes after a raid on Kira: she is determined to serve at the inner palace of Edo Castle called "Ooku".