Hakuoki ~Demon of the Fleeting Blossom~

The Shinsegumi wait to see if Sannan recovers from his violent reaction to "that medicine"—and work to keep Itou from noticing. Chizuru has a moment of truth revealed to her because of the incident. While on patrol, she and the soldiers rescue a young woman who looks almost exactly like Chizuru, who has still been dressing as a boy. Later, as the Shinsengumi take up guard duty for the Shōgun's visit, the three strangers—calling themselves "Oni"—try to kidnap Chizuru. (Source: Wikipedia)