During Japan's Edo period, at the height of Kasuga no Tsubone's influence in the shogunate, a covert force of female ninjas operated in secret. Answering only to Kasuga—one of the most powerful women in the Tokugawa court—this elite group, known as the Kagero Group, handled conspiracies and missions too dangerous or politically sensitive to be addressed openly. When a plot to overthrow the ruling family of the Omura domain is uncovered, the Kagero Group is dispatched to intervene. Led by Kagero (played by Hiromi Takigawa), granddaughter of the legendary ninja Hattori Hanzo, they join forces with the shadowy Yagyu clan to stop the conspiracy before it can bring down the domain from within. In a world ruled by secrets and shadows, these women fight not only for justice—but for survival.

Kagero, the leader of the female ninja serving Kasuga no Tsubone in the Ōoku, rescues a young woman who is being attacked by samurai. This incident leads to the discovery of a smuggling scandal in the Echizen Maruoka Domain. Without hesitation, Kagero and the female ninjas set out for Maruoka to investigate and take action.

Kagero, leader of the Kagero Squad, confronts a clandestine group that plans to seize a hidden treasure and replace the lord of the Dewa Honjo Domain. The squad battles the conspirators to protect the domain’s honor and the treasure’s secrecy