While a phantom killer had been targeting drunkards on the streets, a drunk Sakata Gintoki went home, only to see a Shinigami asking him to help it committing seppuku. Unfortunately, he ended up beating the Shinigami unconscious and brought it home. At the Yorozuya, the shinigami turned out to be a girl named Ikeda Asaemon.
In an alley, the Shinsengumi found the fourth victim, with his neck completely cut through except a small piece of skin. The 18th Ikeda Yaemon identified the cut as "Kimoarai", a technique of the Ikeda Clan, and accused Asaemon of being the culprit.
That night, Asaemon hid under a bridge from the police searching for her, having a dream of executing the 16th Ikeda Yaemon in the past. The Yorozuya rescued her and handed her to the 18th Ikeda Yaemon. There, he revealed that she was completely innocent.
The 18th Yaemon also told the Yorozuya about their past: Unlike Yaemon, Asaemon was an adopted orphan, yet the two still support each other like siblings. Not long ago, the 16th Ikeda Yaemon was discovered to have freed an amount of prisoners ten years before and had to commit seppuku as a punishment, with Asaemon executing him. When his death was publicly known, she left the clan as a traitor to hide the truth.
After listening to his story, Gintoki deduced that Yaemon was, indeed, the true killer, whilst the tsujigiri victims were the freed prisoners. However, using the fact that Gintoki was also one of them, Yaemon forced him to help the Ikeda Clan. He planned to fake Asaemon's death and hid her in a corpse container to get past the Shinsengumi, with the Yorozuya escorting her.
On the way, Asaemon expressed to Gintoki her feeling of incompetence as an executioner, uncapable of using Kimoarai on the 16th Ikeda Yaemon, who she considered as a father. Gintoki then assured her that both he and Asaemon were good people.
While so, Hijikata Toushirou and Okita Sougo still demanded to check the containers and informed the Yorozuya that Yaemon had, in fact, sold Asaemon and Gintoki to the Hitotsubashi Faction, and that the victims were all Hitotsubashi opposers. Having gained confidence, Asaemon opened the way to the 18th Ikeda Yaemon as she chose to die with him to clean the Ikeda Clan's name.
However, Yaemon revealed that Gintoki had indirectly killed her biological father, who tried to sell her to the Hitotsubashi Faction. Gintoki had let himself captured in her stead, yet the 16th Yaemon executed her father and released Gintoki. At present, the 18th Yaemon demanded her to kill Gintoki as she recalled her promise to behead him during his imprisonment.
As soon as Asaemon seemingly chose to kill Gintoki, her brother attempted to kill her. Though, in fact, Gintoki had just drew out her sword and soon attack Yaemon. His past was then revealed: As a child, he killed several prisoners to prove himself worthy of the title "17th Ikeda Yaemon," resulting in the title being given to Asaemon. Afterwards, he conspired with Hitotsubashi Nobu Nobu to gain the title by getting rid of both Asaemon and his father.
At present, the 18th Yaemon lost to Gintoki and got injured. As the assault of the Hitotsubashi Faction continued, he sacrificed himself and entrusted Asaemon to clean the clan's pride. As a result, he was beheaded by Nobu Nobu, who claimed that he himself would be the country's executioner.
Later, upon learning of her brother's death, Asaemon claimed to take full responsibility and committed seppuku, which was actually a way to kill her "Ikeda Asaemon" identity, as she became the 19th Ikeda Yaemon. She then acted as the executioner of the Yorozuya, cutting their handcuffs, her skull mask, as well as Gintoki's left nipple.
- Sakata Gintoki
- Ikeda Asaemon (debut)
- Shimura Shinpachi
- Hijikata Toushirou
- Okita Sougo
- 18th Ikeda Yaemon (debut)
- 16th Ikeda Yaemon (flashback)
- Sasaki Isaburo (flashback)
- Hitotsubashi Nobu Nobu (debut)
- Takasugi Shinsuke