After you see a cinema of a knight, which you don't know his name at the time kills a red dragon, the prologue starts:
"A great darkness shrouded the world. The wind died. The sea raged. The earth began to decay. Only a prophecy kept hope alive in people's hearts. When a darkness veils the world, four warriors of lights shall come. And, after journeying far, four young warriors did at last appear. In the hands of each rested a mysterious crystal."
You play the role of the light warriors. Your job is to defeat the evil four fiends that have been causing trouble for a while now. There's something even more sinister behind it all, though…