In the 1860s in Japan, a new era is dawning. During this time fraught with violent social upheaval, samurai of all walks of life flock to Kyoto in the hope of joining a band of warriors united around their undying loyalty to the shogunate system. In time, this group would become one of the greatest (and most infamous) movements in Japanese history... the Shinsengumi!

Posing as a man, Sei trains with the Shinsengumi and does her best to survive the turbulent times. Councilor Ito Kashitaro proposes an espionage plan with the ostensible purpose of acquiring information from neighboring regions. However, the selection of members to join Ito's group causes controversy for Sei, her secret love Okita, and her secret admirer Saito!