During the height of Babylonian civilization, people built the Tower of Babel in an attempt to reach god. God sees this, and becomes angry with mankind's hubris. He rains thunder down upon the tower to drive people away. In order to keep people away from the tower, god fills it up with giant creatures and evil spirits.
Several thousands of years later, the strongest devil Asmodeous gains control over all of the creatures and spirits that god placed in the tower. He attacks the neighboring towns, and steals all of their golden and silver treasures, as well as the most beautiful maiden in the land.
Your mission of salvation is to rescue the maiden, and destroy the cursed tower in order to return peace to the world.