Lina Inverse and her sidekick Naga the Serpent are happily enjoying lunch when the entire town ducks under cover before an invasion of Marlene Culvert and her legion of bloodthirsty dragons. The cause of the invasion? Marlene is in a feud with her father, the king, over her allowance. Lina leaps into action to defend the village against Marlene, her tetrad knights and her dragons, but her dependable Dragon Slave spell fails her. Right when she thinks she has won, the real battle has just begun.

After an interplanetary war at the beginning of the 21st century, planet Earth has been left in ruins, with much of its ecosystem completely destroyed. Because it was no longer possible to live a normal life on this planet, the inhabitants are forced to move on to other planets where life will, hopefully, be more comfortable.