The story takes place in Edo , now known as Tokyo - which had been conquered by strange alien beings called "Amanto." The samurai then fought against the invaders, but after that they had been defeated Amanto banned all people of the city carrying swords.
The play centers on the adventures of a samurai called Sakata Gintoki , who helps a teenager named Shinpachi Shimura to save his sister from a group of aliens who wanted to make it part of a brothel . Impressed with Gintoki, Shinpachi decides to become his apprentice and work with him as a professional independent in order to pay the monthly rental income of Gintoki. Later, both extraterrestrial save a young girl named Kagura from a group of yakuza who wanted to use his superhuman strength to kill people. After that, Kagura decides to join Gintoki and Shinpachi to work on their own, and the three call themselves "Yorozuya Gin- chan ".