Ruriiro Princess (1992)

Original title: るり色プリンセス

Ruri, a ditzy high school girl who lost her parents in a fire at a young age, is now living a blissful life with her cousin Tooru, for whom she harbours romantic feelings, and his family. But one day her life is thrown into turmoil, when members of the popular j-pop band B-Flash appear before her and reveal Ruri to be a descendant of the Pulsean Moon's royal family. One by one assailants try to take her life, only to be thwarted by Tooru in their attempts. However, the fate of the two is taken to a trial once he receives a mortal wound trying to protect her.