Season 1

The year is 1931, the 64th year of the Meiji era. The 15th Shogun, Yoshinobu Tokugawa, continues to wield absolute power thanks to complete monopolization of a special natural resource known as "Ryumyaku." Supporting the Tokugawa regime from the shadows are the deadly agents of the covert organization known as Nue.

With confidential Nue files having been leaked to their enemies at Kuchinawa, a search is underway for the traitor who provided the information.

Asahi and Yukimura struggle with the nature of their relationship, while the mole leaking Nue secrets is found... or is he?

Asahi has been kidnapped by Janome, and loyalties are called into question all throughout Nue. Will Yukimura be able to save her adopted sister in time? And will her employers in the Tokugawa government even let her try?

Now that her revenge is complete, Sawa doesn't know what to do with herself. With Tsukishima on the run and Elena facing a major change, what will become of the agents of Nue now that their primary target has been dealt with?

It's become clear that Nue agents don't leave the shogun's service and live to tell the tale, so it's up to Asahi to find a way for Sawa to break free of the life of violence she's become trapped in.

After faking Sawa's death, she and Asahi have fled Tokyo for a peaceful life in the country... but can they really escape the cycle of killing?

Sawa's brief respite from the cycle of violence has been irreversibly shattered. But even if she defeats the monster who brought an end to her dream, will she have anything left afterwards?

With her life in tatters, Sawa struggles to find a reason to keep going. Accompanied by another Nue executioner, she decides to look to her past while considering her future.

Asahi is alive, but Sawa has seen too much to ignore the crimes perpetrated by Jin Kuzuhara in the name of the Tokugawa regime. Hoping to secure a brighter future for the girl she has adopted as a sister, the assassin once known as Yukimura takes up her sword once again...