Adventure 21

STORY

Luna Park II is a state-of-the-art commercial airplane flying from Tokyo to New York. Among the passengers are a boy named Isami and his pet rabbit, Mimi. Also on board are Sullivan, the designer of Luna Park II, and his daughter, Carla. Sullivan is actually the creator of Luna Park I, the original version of the plane, which tragically exploded, resulting in Isami losing his parents. As a result, Isami initially harbors resentment towards Sullivan. However, over time, he comes to understand Sullivan's true character and begins to change his attitude. On the other hand, Mimi undergoes surgery performed by Dr. Frankenstein, transforming himself into a human-like creature, and takes on the name Mimio. Mimio then becomes an assistant test pilot aboard the underground train, also named Luna Park II, designed by Sullivan. Mimio, Isami, and Carla embark on a journey to a mysterious underground nation.
(This is a remake of The Mysterious Underground.)