This is the only chapter in the King's Quest series where the action takes place in real-time and within the allotted time limit, as the events of the game cover about 24 hours.

Some activities must be completed during the day, while other puzzles can be solved only at night (the nightfall in the game happens either at 9 pm or at a certain point in the plot[4]).

Rosella agrees to undertake a quest for both the talisman and the magic fruit and goes out undercover, dressed as a peasant girl.

Rosella manages to find the fruit, traversing a dangerous underground passage and swamp, but is captured in Queen Lolotte's perilous mountains and imprisoned in her castle.

Rosella reluctantly agrees and captures a unicorn, steals the golden hen and recovers Pandora's Box for Lolotte who intends to use the items to increase her evil power and influence.

Although Rosella's primary quest is to retrieve the magic fruit needed to save King Graham, it is possible to return to Daventry without completing this task, but this leads to a tragic alternate ending to the game where Rosella returns to Daventry in time to witness her father die instead of saving his life.

A second alternate ending exists where if Rosella is caught after escaping from her room, she will be forced to marry Edgar and spend the rest of her life in Tamir.

[6] With the SCI engine, Sierra dropped disk-based copy protection schemes in favor of requiring the user to enter a word from the manual, as the new-generation games were designed primarily to be installed and run from a hard disk.

King's Quest IV was the first commercially released game for IBM PC compatibles to support sound cards instead of only the standard built-in speaker.

The new SCI engine allowed the game's designers to incorporate an orchestrated musical score along with more complex sound effects, a previously unattainable feat.

I wanted King's Quest IV to have some pressure applied to you: a timed game, taking place over a 24-hour period, so you roam around during the day and eventually it turns to night.

The new engine was designed for then-current IBM-compatible hardware (i.e. 8–16 MHz 286 or 386 machines with EGA or VGA graphics and a hard disk) and ran poorly on older 8086 computers.

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

[26] Page 6's John Sweeney wrote the game was "undoubtedly excellent", but personally he preferred King's Quest III.