The version 2.14 (1988-3-15) was included in many of the King's Quest collections over the years, with the disk based self-booting copy-protection removed.

According to the introduction, for as long as he could remember, 17-year-old Gwydion has been held captive by Manannan as his servant, cooking and cleaning for him in his home atop a large mountain in Llewdor.

From this vantage point, and with the help of a telescope, the seemingly all-knowing wizard watches the countryside, the shoreline and vast ocean to the east and an endless desert to the west.

After solving many puzzles to obtain the spell ingredients, Gwydion turns Manannan into a cat and is free.

After sailing to the coast of Daventry, he manages to use another spell to put the pirates to sleep and escape, stealing their treasure in the process.

Alexander traverses a series of mountains before finally reaching the outskirts of Daventry, where he discovers Rosella about to be slain by the dragon.

The Magic Mirror, which has been clouded by a mystical darkness since the night Prince Alexander was kidnapped, is restored, and King Graham decides to pass on his adventurer's cap to one of his children.

The actions taken by Gwydion in this story lead directly to the events that begin King's Quest IV.

The series's designer and writer Roberta Williams said: "My previous games, from Mystery House to King's Quest II, were all great.

[5] By the mid-1980s, the new generation computer platforms such as the IBM AT, Amiga, and Macintosh were faster and sported more memory as well as standard hard disks.

[9] King's Quest III was the first Sierra game to be DOS-based instead of using a self-booting disk, as well as the first to feature EGA and Hercules graphics support.

The game's manual contains a short prologue story by Annette Childs that tells of Manannan's previous slaves and their deaths.

However, to complete King's Quest III, the player needs to create a number of magic spells through alchemical formulas that are only available in the game's manual.

Many considered the process slightly overdone; 140 of the 210 possible points in the game are obtained through simply doing what the manual says, leaving less room for real puzzles.

Starting with King's Quest IV, copy protection in later Sierra games required less information from the manual.

The novelization is written in the form of an interview between Derek Karlavaegen ("Guidebook to the Land of the Green Isles") and Alexander sometime after the events of the third game.

[11] According to Sierra On-Line, combined sales of the King's Quest series surpassed 3.8 million units by the end of March 1996.