Gintama

The story

In a world where aliens have invaded Edo Period Japan, skyscrapers, trains and motor bikes have replaced the simple life of Earth inhabitants. One man however, still carries the soul of a samurai, Gintoki Sakata, otherwise known as Yorozuya Gin-san. As reckless as he is, Gintoki carries his own resolve and is ready to take on any challenge with his fellow companions.