This is the second game in the series about the school girl Yuna Kagurazaka, who fights crime in cosmic battles. Eien no Princess continues the story of the first game. Yuna has defeated the 13 Servants of Darkness, and their leader Lia has become a friend, fighting crime on her own in a superhero TV show. Life seems to continue normally, the only trouble being Erika, a snotty high school girl who sees herself as Yuna's biggest rival. She challenges Yuna to a fight, but both are spotted by the titular starship "Eternal Princess", commanded by the pretty Princess Mirage, whose task is to stop violence in the whole galaxy. What begins as a misunderstanding ends as a serious threat to the Earth...