The Winter's Banked Fire (Saito) - S0.E8

Hajime Saito is attracted by a fine sword in a display case and rattles on about the importance of a good sword to Chizuru, who starts laughing at his passionate outburst. Flashback at the Shinsengumi, Chizuru is asked to be an undercover geisha by Kondo and Toshizo Hijikata. Chizuru becomes extremely uncomfortable at the thought of the dangerous mission, but Saito immediately proffers himself and Susumu Yamazaki as bodyguards for Chizuru.