Fan Casting The Hitchhiker's Guide To The Galaxy

Arthur Dent, a perfectly normal English earthman, has his house destroyed, and the Earth soon follows to make way for a galactic bypass system. With his friend Ford Prefect (who reveals himself to NOT be a human, but rather an alien from somewhere near Betelgeuse), Arthur meets with new (and old) friends as they travel across the galaxy in The Heart Of Gold. But there's just one problem. The ship's "owner" actually stole the ship illegally, and is currently being tracked by the Galactic Federal Police. Also, how was the Earth really created, and what was it REALLY for?