Yuki is the last surviving royal of the House of Takemikazuchi or Takemikazuchi no Hime (たけみかずち　の　ひめ), who live in a futuristic post-apocalyptic isolationist world where they use their skills as former Mikado guards to become hired assassins. The wise old sage Kuka, who was once Yuki's mother's bodyguard, gives Yuki information that changes her life—and her destiny. She discovers that Byakurai has a dangerous connection to Yuki. After learning this information she chooses to leave the House of Takemikazuchi. She soon encounters Takashi, leader of the rebel movement, who offers Yuki a chance at revenge—and perhaps love. They soon discover similarities for they are both trying to escape the past to start new lives....