hen Leela is insulted by a group of space-rednecks (like regular rednecks, but in space) she enters the Planet Express ship in a demolition derby. She emerges victorious, but when she brings the damaged ship home and the Professor sees the fuel gauge, he's enraged by the hit he's going to take at the Dark Matter pump. Now the crew have to find a way to break Mom's stranglehold on starship fuel, even if they have to wade through a Lord of the Rings-inspired fantasy-land to do it!

Overview from themoviedb.org