Hijikata returns from another successful recruiting trip to Edo with 52 new men. One of them, Nakamura Goro, is convinced Sei is a girl the moment he lays eyes on her. Irresistibly attracted to her, he is determined to uncover her so he can have her as a woman. How will Sei handle this new threat from within the ranks?

Doctor Kondo, a respected expert in western medicine, visits the troop. As an act of kindness, the doctor offers to give physical exams to the entire troop, and the men are ordered to strip down to their loincloths. Now Sei seems to be caught in a trap she can't get out of. She's managed to fool everyone else into thinking that she's a boy, but how can she possibly fool a doctor?

When Sei gets wounded, Soji takes her to Doctor Matsumoto, an old family friend who knows her secret. While in his care, Sei tells him of the resentment she feels toward her father, who neglected his family to pursue his medical practice. Matsumoto reveals the truth about her father and the sacrifice that affected his family's destiny.

Sei devotes herself to becoming an ideal bushi, or warrior, and accompanies the Mibu-Roshi to Osaka. There, she finds the man responsible for killing her father and brother. Desperate to avenge her family, Sei uncovers his hideout with the help of a friend, but they are soon discovered and her companion is slain. Is Sei ready for the hardships of the Mibu-Roshi? Or should she return home to lead the life of a normal girl?

Sei has returned to the Mibu-Roshi, but Soji hardly seems happy about it. He still believes that the Mibu-Roshi is no place for a girl. Sei makes an agreement with him that if she can't score one hit on him in three days, she'll leave for good and return to living a normal life. However, Sei's got her work cut out for her, as Soji is a master swordsman...

Ordered by Katamori-sama to assassinate Captain Serizawa, Captain Hijikata holds a secret meeting with the other leaders in the Mibu-Roshi to plan the murder of their charismatic comrade. Soji breaks in on the meeting, but rather than pleading for his friend's life, he offers to kill him.

Sei seeks out Saito Hajime to help her master a difficult sword technique, and Saito is confused by his amorous feelings for Sei, not knowing that she is a girl in disguise. As if things weren't complicated enough, it seems a truly male Sei look-alike has taken a fancy to Saito - and plans on seducing him!

Rumors emerge that the Choshu clans are gathering in Kyoto, conspiring to set fire to the capital and make off with the Emperor. In a skirmish with the plotters, Soji is badly wounded, and now Sei finds herself surrounded and outnumbered. Will she find the strength she needs to survive?

Akesato the courtesan has been instrumental in hiding the fact that Sei is a girl by pretending to be "his" lover. But Yamanami, another member of the Shinsengumi, has fallen madly in love with Akesato. As he struggles with the conflict between his comrade Sei and the love he feels for Akesato, he stumbles onto Sei's secret.

Yamanami and Todo prepare to be sentenced to death for insulting officials at the Rokkaku prison after witnessing prisoners being ruthlessly murdered. In a surprising turn of events, rumors fly that the Shinsengumi were the actual culprits behind the abuse of the prisoners. Meanwhile, Todo has fallen in love with the prostitute who witnessed them enter the prison. Can he win her love and convince her of his innocence?

With increased responsibility, the Shinsengumi must do some major reorganizing. Soji, Nakakura and Saito are named troop captains. Despite Sei's desire to be placed in Soji's group, Yamanami assigns her to be his personal attendant, as he wants to keep her out of harm's way. Sei works diligently at her assigned duties, but will she be able to hold herself back when Soji and his men face danger?

Orphaned four years ago by an accident that took her parents and her memory, 16-year-old Momoka Futami travels to Mitsurugi City upon receiving an invitation from the Mitsurugi House, her father's very powerful relatives who offer to take her in. What awaits her far exceeds her fears and expectations: a spiritual sword, Suzukaze, and a tumultuous battle.