Set in June 1863, the narrative centers on an amnesiac man who arrives at the Mibu Roushigumi headquarters in Kyoto. Vice-commander Souji Okita takes him in, bestowing upon him the name Jinsuke Tachikawa, and he starts his life as a group member. As the Mibu Roushigumi—later recognized as the Shinsengumi—rise to prominence during the chaos of the late Edo period, Jinsuke and his fellow soldiers are drawn into the era's turmoil. By the time Jinsuke fully recovers his memories, the world surrounding him has been irrevocably altered.