The book begins shortly after the ending of The Colour of Magic, with wizard Rincewind, the tourist Twoflower, and the Luggage falling from the Discworld.

The Archchancellor of Unseen University attempts to obtain the spell, but accidentally summons the Luggage on top of him, crushing him to death.

Rincewind and Twoflower encounter a sect of druids who have assembled a "computer" from large standing stones, and learn of the approaching red star.

Rincewind, Twoflower and Bethan are attacked by a mob of people who believe the star is coming to destroy the Discworld in response to the presence of magic.

The trio escape into a magical travelling shop, one of many that sell strange and sinister goods and vanish inexplicably the next time a customer tries to find them.

As the star comes nearer and the magic on the Discworld weakens, Trymon tries to put the seven spells still in the Octavo into his mind, in an attempt to save the world and gain ultimate power.

However, the spells prove too strong for him and his mind becomes a door into the "Dungeon Dimensions", home of terrifying eldritch creatures.

(ISBN 978-0-06-168596-5) The Mob Film Company and Sky One produced a miniseries, combining both The Colour of Magic and The Light Fantastic, broadcast on Easter Sunday and Monday 2008.

Dave Langford reviewed The Light Fantastic for White Dwarf #83, and stated that "Abandoning the cruel fantasy parodies of his previous book, Pratchett leans more heavily on the one-line gags: the result isn't as pointedly funny, but still evokes more laughs than anything else around.