Gintama: Yoshiwara in Flames.

Upon meeting a young boy named Haruta who makes a living as a pickpocket, Gintoki discovers that he is pickpocketing out of a desire to meet his long-lost mother, Hiwa, Yoshiwara's number one courtesan. Gintoki and his friends venture to Yoshiwara to fulfill Haruta's wish, but standing in their way is Housen, the Night King who rules Yoshiwara.