The year is 2199. The human race has been crushed in their war with the Gamilos, driven into underground cities by the invader's assault. Scientists estimate they have only a year left. The young officers Susumu Kodai and Daisuke Shima receive a mysterious capsule from a ship that made an emergency landing on Mars and return with it to Earth. It contains humanity's last hope: the planet Iscandar on the other side of the Magellan Galaxy has the technology to defeat the Gamilos and restore the planet. The space battleship Yamato is entrusted with this task, but they have only one year before humanity ends.

Life isn't easy in feudal Japan... especially since the aliens landed and conquered everything! Oh sure, the new health care is great, but the public ban on the use of swords has left a lot of defeated samurai with a difficult decision to make concerning their future career paths! This is especially true if, as in the case of Gintoki Sakata, they're not particularly inclined towards holding a day job, which is why Gintoki's opted for the freelance route, taking any job that's offered to him as long as the financial remuneration sounds right. Unfortunately, in a brave new world filled with stray bug-eyed monsters, upwardly mobile Yakuza and overly ambitious E.T. entrepreneurs, those jobs usually don't pay as well as they should for the pain, suffering and indignities endured!