Fushigi no Umi no Nadia: The Secret of Blue Water is one of the several games based on the anime series of the same name. The game assumes familiarity with the story of the anime, taking the player directly into the time frame of late episodes, where Grandis and the jewel thieves have already joined Jean and Nadia on their travels with Captain Nemo on his submarine "Nautilus". Following a dramatic scene that reveals more about Electra's past, the crew is stranded on a mysterious island. Jean, Nadia, Marie, and the lion cub King decide to explore it, and discover an ancient civilization in the process.

[From Moby Games]