The power of the Staff of Gnilda, the artifact that protects the city to Llylgamyn is fading. Queen Airasu's sister, Sokusu went missing a year ago, along with the evil mage Thailand Rossum. The Queen has called upon adventurers to defeat Thailan Rossum and find her sister. Your party of adventurers has heeded this call.

Wizardry Gaiden is a side story Wizardry game for Gameboy. It is an original, Japanese-only title, and is not a port of any computer versions. Its developer, ASCII, was also the developer that created the Wizardry 1 through 6 remakes for Famicom and Super Famicom, and as such Wizardry Gaiden retains much of the same look and feel of other console titles in the series. The gameplay system most closely resembles Wizardry V (released the following year for Super Famicom), with the addition of long-range weapons, enhanced spells, and auto-mapping.

The player creates characters from the stock Wizardry classes and races seen in other games in the series, such as fighters and wizards, and then forms a party of up to 6 to explore the solitary dungeon. The player transverses the six floor dungeon in 1st person, fighting random encounters and gaining experience to level up. Thanks to the introduction of auto-mapping, it is possible to complete Wizardry Gaiden without the use of graph paper, unlike other early entries in the Wizardry series.