Based on the game by Valkyria.

Dragundaala, a country belonging to the descendants of dragons, has been conquered by an army of demons. With the king and queen captured by the demon army general, Ginyol, princess Catue attempts to rescue them, but gets caught. All is not lost, however, as Ginyol agrees to free the king and queen, and withdraw his army entirely if princess Catue can endure his sexual acts of depravity for 7 days.