The story is set in an alternate-history late-Edo period, where humanity is attacked by aliens called "Amanto" (天人, "Sky People"). Edo Japan's samurai fight to defend Earth, but the shogun cowardly surrenders when he realizes the aliens' power. He agrees to an unequal contract with the aliens, ceding power to them, and also places a ban on carrying swords in public and allows the invaders to enter the country. The samurai's swords are confiscated and the Tokugawa bakufu (shogunate) becomes a puppet government. The series focuses on an eccentric samurai, Gintoki Sakata who works as an odd-jobs freelancer. He helps a teenager named Shinpachi Shimura save his sister Tae from an Amanto group that wants to send her to a brothel. Impressed by Gintoki, Shinpachi becomes his freelance apprentice to pay the bills and learn more about the enigmatic samurai. When the pair rescues a teenage alien girl with super-strength, Kagura, from a Yakuza group, they accept her into their odd-jobs freelancing business, and the three become known as "Yorozuya" (万事屋, 'Store of 10,000 business' or 'We do everything').
