Katsugeki Shoujo Tanteidan OVA 活劇少女探偵団 [1986]

St. Godama Jogakuin is famous as a school for young ladies. It is a venerable academy where royal aristocrats from all over the world also attend, and Yuriko Edogawa, Aoi Ichitani, and Ingrid, Shizuka, and Grebel who go to school were very close friends. At one point, Yuriko and Shizuka are worried because Ao is missing, but both are also targeted by someone. Behind the series of incidents, the school president's ambitions were hidden, and the witch was in a new weapon developed by Ao's father, Dr. Ichitani.