Discworld is a place of magic. As such, there are magical people, like Wizards, floating around. Rincewind is a wizard - he just happens to be amazingly bad at it. There are 8 great spells (8 is the magic number on Discworld) and one of them got into his head by mistake. Now, no other spells will dare get into his head because they're too frightened of the Great Spell. Twoflower is a tourist from the Counterweight Continent, and sports all sorts of strange devices. His most interesting item is the Luggage, which is made out of a magical wood call Sapient Pearwood. It has lots of little legs, a mind of its own, and things disappear inside it never to be seen again. But, if need be, it can somehow take your laundry and clean it for you, or produce certain items out of nowhere... At the end of the first book in the Discworld series, The Colour of Magic, Rincewind is hanging off the edge of the world (it's a disc, so of course it's flat), and Death's understudy is trying to convince him to die. But Wizards have a special privilege - they can only be taken by Death himself. Twoflower and the Luggage are... somewhere around. And so begins The Light Fantastic. (So named because that's what you can see if you're hanging over the edge of the world). Rincewind somehow survives, and further survives many things which should mean his instant death. Much to his dismay, he is joined in his quest by Twoflower and the Luggage. But after a while he begins to realise something - that he's constantly being saved from the jaws of death because the Great Spell wants to keep him alive. And the reason for this, Rincewind reasons, cannot be good. In fact it would mean the end of the world. Oh, and could it be that the great A'Tuin, the turtle carrying Discworld on its back) is changing course? (Just to complicate matters even further...) There are some lovely characters in this second novel in the Discworld saga, notably Cohen, the aged barbarian with no teeth, and Bethan, his reluctant damsel in distress.
The Light Fantastic Originally published in Shvoong: http://www.shvoong.com/f/books/science-fiction/27163-light-fantastic/