Lesson 504 is the 504th chapter of the Gintama series.
In a flashback in Iga, a young Hattori seemingly fell asleep while learning about the history of the Oniwabanshuu and received a kunai in the head from the teacher. In fact, it was just a doll, and the real Hattori had been reading Jump outside the class. As a result, he and the teacher engaged into a ninja fight, which Sacchan watched in boredom.
At present, the Yorozuya, in disguise of the Shogun, were making annoying demands to Hijikata. As Sacchan thought about Hattori's refusal to take part in the plan, she received news that the guards were attacked from behind. However, she instantly killed the informants, confirming that they were the enemies in disguise. The guards also turned to kill the group, but were quickly defeated. Tearing the masks of the insurgents, Sacchan realised that the enemy also used shinobi.
On the main spacecraft of the air route, the beheaded Shogun fell down before Maizou's eyes, as Hattori took the Shogun's head and left. Nearby, an escort ship exploded, and the shinobi, disguised as the guards on board, began their killing spree. Watching the scene on a Harusame spacecraft, Kamui remarked the low security and expected Soyo-hime to be killed by the shinobi. However, Okita stepped out with the princess still alive after killing all of the insurgents, which attracted Kamui's attention.
Characters in order of appearance
- Tokugawa Shige Shige: (To the Oniwabanshuu) The duty of the Oniwabanshuu is not to protect the Shogun. It is to protect the Shogun's duty. And a Shogun's duty is to protect his people and his country even if he must risk his life to do it. If a day comes where you become part of the Oniwabanshuu and if a day comes where I become Shogun. Perhaps we can fight together for the sake of this country. I look forward to that day.
- Hattori Zenzou: You cannnot protect the country as the Shogun. By giving your life, you've accomplished your duty as the Shogun, and I've fulfilled my duty as a shinobi.
- On page 17 of this Lesson, Kamui's face was drawn with an expression similar to that of Songoku in the Dragon Ball series.