Good and evil are eternally at war. The forces of Light and Darkness have forever been locked in conflict, ever since Time's beginning, as they will be until the end of the universe. Sometimes one holds dominance, sometimes the other, but whenever one force threatens to grow too strong, a champion is chosen to restore the balance.
Frequently, that champion has no idea of her destiny beforehand.
Such was the case when Yuna Kagurazaka became the Savior of Light: an ordinary girl from late 23rd-century Earth, called to fill an extraordinary role. Cheery and outgoing, she hardly seems like a warrior at all — but the thirteen Frauleins of Darkness were defeated by her hands, and with their hearts freed, they became her allies; some of them go so far as to call her friend, as she calls all of them.
As the Savior of Light, Yuna has already fought many battles, made many friends, and foiled numerous plots by the forces of evil. Yet underneath it all, she's still the same girl she's always been, cheerful and innocent, and eager to make even more new friends.
But with the forces of Darkness always planning their next move, Yuna needs every friend she can get.