Lesson 503 is the 503rd chapter of the Gintama series.
Watching Nobu Nobu being taken away on an ambulance, Kamui and Takasugi discussed about his ability as the next Shogun, referring to their plan on assaulting the current Shogun.
To move Shige Shige to Kyou, three doubles were prepared. One of them would stay in Edo, while the others would travel by different means, with the real Shogun going by air. The last double's group travelled by land, which was the most dangerous route. Therefore, the Oniwabanshuu, as well as Kondou, Hijikata, Kagura and Shinpachi, was employed to protect the double, who turned out to be Gintoki.
Meanwhile, in Edo, Yamazaki, was a guard of the staying double, wondered where Okita was. On air, the guards were completely assured that the Shogun would be safe, provided that Hattori was with him. Nevertheless, at the Shogun's place, the shinobi immmobilised Maizou and beheaded Shige Shige.
Characters in order of appearance
- The title of this Lesson is a Japanese idiom about something very unexpected happening, which does happen many times in this Lesson and future Lessons in this arc.