This is the second Discworld game. Death has gone missing. A hero is needed to bring him back. But there's only Rincewind, incompetent wizard and highly trained coward. You won't catch Rincewind running away. He's too fast. Unfortunately, he's all there is that stands between people and the horrible prospect of immortality. No one wants that, do they? As Death himself says: HAVE FUN.
This game is also known as Discworld II: Missing Presumed...?! in Europe.