From the back of the box:

When Kuros™ last did battle with the Evil Wizard Malkil™ atop Icefire Mountain, he raised his Ironsword™ in triumph and glory...or so he thought.

Suddenly, a powerful bolt of magic has robbed Kuros of his armor, memory, and honor. But the distant presence of evil stirs in his mind, leading him to the once fair city of Piedup, the very same place where the villainous soul of Malkil survives.

Without his armor, Kuros will need crafty disguises to travel undetected, ready to do battle as a wizard, nobleman, or thief. His quest will take him from the depths of the dungeon to the palace containing riches beyond belief—building strength, perfecting fighting skills and acquiring rare knowledge of magic along the way. The time has come for Kuros to turn his visions of power...into reality!

From Wikipedia:
Wizards and Warriors III - Kuros: Visions of Power is the final video game in the Wizards and Warriors trilogy. It was released for the Nintendo Entertainment System in 1992 by Acclaim and developed by Zippo Games for Rare.

Kuros is free to travel between all three areas, but will need certain skills to advance further. These skills come from joining three guilds in the game, each revolving around a certain class; Knight, Thief and Wizard. To advance in rank at each of these guilds, Kuros must find the statue which corresponds to the guild's level; bronze statues for first level guilds, silver statues for second level guilds and gold statues for third level guilds. Each class has its own unique abilities, which evolve throughout the course of the game; Kuros is free to switch between classes at any time, except during boss battles or during guild tests.

Due to the game's open-ended nature, exploration is necessary to find all necessary items and secrets. Most doors can be entered with a key, which can be purchased at an inn; however, some passages can only be accessed using certain skills. Most of the important items in the game are guarded by boss monsters.

Unlike the past games in the series, there is no continue mechanism; once Kuros loses all of his lives, the game ends. There are no hidden continues, nor is there any way to restore a life once its been lost. Even though there is no continue mechanism, the game is drastically easier than its predecessors. It is possible for Kuros to avoid almost all damage by using the appropriate class in its respective area.

Source: Wikipedia, "Wizards and Warriors III," available under the CC-BY-SA License.