Ah! The Secret of the Queen and the Goddess - S1.E9

Belldandy wins the Miss NIT contest and becomes Campus Queen. Sayoko and Toshiyuki try to uncover Belldandy's identity by setting up revealing situations where Belldandy would have to use her magic, but with big sister Urd watching, that isn't so easily done. Toshiyuki manages to put Urd to sleep by playing Enka music, and Sayoko kidnaps Keiichi. To get Keiichi back, Belldandy might have to reveal to Sayoko the truth about herself!