Farewell, Shinsengumi Arc is the 65th arc in Gintama, continue after the previous arc immediately. It is also one of the most important arcs, following the rebellion of the Shinsengumi and Jouishishi samurai in order to help their leaders get out of the prison and ruin the darkness caused by Hitotsubashi Nobu Nobu, who had become the new Shogun after Tokugawa Shige Shige's death.
Following Tokugawa Shige Shige's death, Matsudaira Katakuriko suspected of the new Shogun's role in the assassination, Nobu Nobu ordered an investigation on Shige Shige's death, which was carried out by the Mimawarigumi. As a result, Matsudaira and Kondo were sentenced to death for being unable to protect Shige Shige. The Shinsengumi was disbanded, and its members became homeless.
In reaction to the former's Shogun's death, Katsura claimed that he would keep his promise to Shige Shige no longer as his enemy, but as his friend. Later, disguised as a hostess in Snack Smile, he helped Sakata Gintoki, who was arrested for punching the new Shogun (thus making him lost his memory,) and his friends flee from the Mimawarigumi, and was imprisoned as a result. In jail, Katsura convinced Kondo to join him and freed him, as well as Matsudaira out of the prison. Meanwhile, the Shinsengumi agreed to ally with the Jouishishi to rebel against the new regime.
As the prisoners managed to survive the Naraku's assassination attempt and successfully escaped, the newly-formed Alliance went on sea to the Kokujou island to rescue them and were attacked on the way. Upon reaching the island, the Alliance climbed on a rock wall surrounding it, only to be attacked by the Naraku again. At the same time, Katsura and Kondou, having parted from Matsudaira, tried to reach their allies, yet Katsura was gunned down by Sasaki. Soon, the two were ambushed by the Mimawarigumi. Luckily, the Shinsengumi arrived on time and managed to save Matsudaira and Kondou before Sasaki could shoot the latter. Hijikata and Sasaki then engaged into a vicious battle, during which the past of Sasaki and the Shinsengumi was shown:
Four years ago, the Shinsengumi was established as the "Roushigumi" as an attempt to get rid of the Jouishishi and any potential signs of a revolution by the ronins. After several days, under Kondou's lead, the organization quickly got into order. In their first mission, they had to guard the Hitotsubashi family, let them assassinated by the Naraku and commit seppuku for their "failure." However, Sasaki managed to foil the plan and save the Shinsengumi. As a result, the Tendoshuu had Mukuro killed his wife and unborn daughter, whom he named "Nobume." At the scene, he spared Mukuro's life and requested her to kill him as his own revenge, since he could not protect anyone nor cut down the current barbarous era. After the tragedy, Sasaki served the Hitotsubashi Faction, conspired with the Jouishishi, brought down the Tokugawa Family's reign and act as the people's enemy, while his true purpose was to ignite a revolution to end the samurai's era and himself.
In the meantime, the fight between the two police forces was interrupted by an explosion from the Naraku Faction's arrival, and Sasaki used all of the Mimawarigumi to fight back.
Characters in order of appearance