In the 19th century, the Aoi clan moved from Japan to Russia and acted as a government intelligence agency and was given a secret city known as "Labyrinth 4" which was in the midst of prosperity. In the present age around the end of the 20th century, Princess Natsu, a descendent of the clan, attends a university in Moscow and invites Galan, a Russian youth, to her hometown.

Galan and the others run away from Nastassja and Elora, but Natsu's Aunt Shinka, is injured. Natsu blames her father Shigemitsu Aoi as she thinks that her aunt's injury was the work of Datenoshin Kagami upon Shigemitsu's order. On the other hand, Shinka says it was not Datenoshin Kagami. And then, a beautiful woman, Carrie, who says she's from Interpol appears...