The Kingdoms of Dolhr, Grust, and Gra band together to wage war on the rest of the continent Archanea and defeat the Kingdom of Altea. King Cornelius is slain in battle but his son Prince Marth is able to escape the invasion thanks to the sacrifice of his older sister Elice. He and a small group of retainers find refuge on the island nation of Talys, where they spend the next three years in hiding under the royal family's protection. Marth lives a peaceful life in Talys, enjoying the beauty of the island and the friendship of its pegasus-riding princess, Caeda. But he is uneasy, knowing soon the day will come that he must take up arms. That day arrives when Caeda comes to Marth and his retainers in a panic, telling him that the castle town has been attacked. After some close calls, they manage to defeat the assailants and save the city. Realizing that his presence may bring further danger to his new home, Marth decides that now is the time to set off. He journeys to raise an army with which to reclaim his kingdom.

Yuna Kagurazaka, a clumsy and sweet sixteen year old girl, had her life drastically changed when she won an intergalactic contest for the person with the purest heart. Now, she is an intergalactic superhero and magical girl known as the Savior of Light. She pilots the mecha El Line to maintain the peace of the universe. But Yuna’s entire world is shaken when she is wrongfully accused of destroying a city with El Line. She is captured and taken prisoner by Misaki Ichijouin, a special agent from the Galaxy Alliance. However, Misaki soon realizes that she has been deceived, and teams up with the rest of Yuna’s friends to free the Savior and save the galaxy before an evil force is restored to power.

Just when everything seems peaceful again for Yuna and her friends, a new enemy appears in the form of three robotic sisters. Yuna must once again become the Savior of Light to fight this strong, new evil.

The fifth season of .