Shizuma Origasa, once a renowned samurai in the Aizu Domain, has fallen on hard times following his home region's crushing defeat against the new imperial government. To make ends meet, Shizuma now works as a rickshaw puller in Tokyo. Meanwhile, he tirelessly searches for his missing fiancée, Sumie Kanomata, the younger sister of his close friend Gennosuke, who had entrusted Shizuma with her safety in his final moments.

After foiling an assassination plot, Shizuma is hired by the police force, and he uses this opportunity to further his pursuit of Sumie. However, he soon lands in a whirlpool of political conspiracies involving government loyalists, persistent rebels, cunning courtesans, meddlesome foreigners, and even a mysterious yakuza member, Kyoushirou Shuragami.