Toushirou Hijikata, Demonic Vice-Commander of the Shinsengumi, gets a cursed sword that entirely rewrites his psyche, transforming him from a hard-boiled, no-nonsense cop into a hopeless otaku. As he fights to remove the curse, Itou Kamotarou, an ambitious new member of the police department, seizes the chance to topple Hijikata in his desire for prominence within the organization. However, Itou's strategy is proven to be more diabolical than anybody expected, putting the Shinsengumi's entire survival in jeopardy. The Yorozuya team is unexpectedly surprised by a prospective new member in another time and place. In front of them stands a fascinating young lady called Pirako Doromizu, who hides a tendency for severe violence behind her cheerful, upbeat demeanor. However, Gintoki and the others were unaware of what was going on.