The Rites of Rulership are about to commence, and the victor will be given the crown. The Hero enters the contest with the assistance of Erasmus, Rakeesh, and many old friends from previous entries in the series. The Hero competes against competitors Kokeeno Pookameeso, Magnum Opus, Gort, and Elsa Von Spielburg (who returns from the first game.)
As the Rites commence, however, an unknown assassin begins systematically picking off each of the contestants. Each contestant is murdered by a poison dagger, and they all are murdered near Dragon Pillars, the objects used to keep the Dragon of Silmaria locked up. After completing the third Rite, defeating the Hydra, Rakeesh is attacked by the assassin and, depending on the course of action chosen by the player, either lives or dies.The conspiracy is eventually unraveled and the Dragon, having been released due to the destruction of the Dragon Pillars, is defeated.
...
The fifth game is arguably a different genre from the first four; while the first four are mostly adventure games incorporating role-playing elements; the fifth game is a role-playing game incorporating some adventure elements. For instance, the fifth game has a wide variety of weapons, armor and magical items, whereas the first four do not. Also, in the fifth game nearly every major mission consists of going to some place and defeating some monster in physical or magical combat. Additionally, the controls and battle system are substantially different from those of the first three games and have taken the variations of the fourth game even further.
Also differentiating the fifth game from the first four were an impressive soundtrack by Emmy-winning composer Chance Thomas and a new graphics engine programmed by Eric Lengyel.
Source: Wikipedia, "Quest for Glory V: Dragon Fire", available under the CC-BY-SA License.