Long, long ago the world was in a state of chaos, where demons caused evil & tormented all. That changed when Solomon, a great king & magician, invented a magical formula which he wrote inside a secret book called "Solomon's Key". This book arrested and sealed away all evil demons into a constellation sign which was hidden. "Solomon's Key" restored light and peace to the world. Upon hearing this legend, a taoist monk searched for a long period of time to find "Solomon's Key". After locating the constellation sign, he discovers the "Key". Once in his grasp many dreadful demons were freed from the magical power of this book. The world was brought back to chaos and darkness. Everything on earth was now under control by the demons just like the pre-creation days. King Yutra from the fairyland called "Lyrac", ordered the wizard, Dana to restore order back to the world. Dana accepted this mission and stepped into the forbidden land of the "Constellation Sign".
--From the NES Solomon's Key instruction manual.