The story: You are Sir Graham, a knight of the Kingdom of Daventry who has been summoned by King Edward the Benevolent to retrieve the 3 stolen treasures of the realm. If you should succeed you will be proclaimed his successor (Edward is old and has no heirs). Graham spends the game searching the kingdom for the treasures and encounters many puzzles and adversaries along the way.
This is the first King's Quest game released way back in 1984 (19 years old as I type this) and unsurprisingly is by far the simplest and most primitive of the series. The game is fairly short (the only necessary quests you need to do are the reclaiming of the 3 treasures - everything else is optional) and practically all of the puzzles you encounter are from well-known fairy tales, including Rumpelstiltskin (did anyone actually spell his name correctly in his challenge?), Little Red Riding Hood (well the wolf at least), Hansel & Gretel, Jack & the Beanstalk and many others.
The game is operated by text commands typed on the keyboard (search, pick up, talk, look etc.) with the arrow keys controlling movement. Simple stuff really, but hey it worked and it would remain the standard control system in the series until King's Quest 5 (which replaced the text commands with an icon-based system using the mouse).
All in all its nothing special by today's standards but worth a look if you're interested in seeing how the entire King's Quest series began. The game was re-released in 1990 with updated graphics and the aforementioned icon system replacing the text commands but from what I've heard the puzzles and the like all stayed the same. A classic of its time.