Gintama is set in a period of relative peace after Edo was invaded by the Amanto and the inhabitants had no choice but to accept these new outlanders as their new neighbours. It depicts Edo after it had been conquered by the aliens, and how it looks after they brought modern-day technology into a samurai country of ages past. Most of the story in Gintama is set in Edo itself, or in the sky above it, but the reader is also taken a few other places for various reasons.