Gintama is a live action movie adaptation of the manga, which is largely a comedy but which also has some dramatic moments. I bought my copy brand new.
Review:
This takes place in an alternate Edo-period Japan in which aliens have invaded the country and taken control, outlawing swords. This technically starts in a cafe, where Shinpachi first meets Gintama, a former samurai. However, that's just a fake beginning: the real beginning is a quest to capture a beetle (Kagura just wants one, while Gintama hopes to sell it for a profit). And the actual for-real beginning is when Gintama learns about a serial killer, and a dangerous sword. The killer may have murdered a friend of Gintama and his group, so they go after him in an effort to find out the truth and stop him from killing again.