Following the latter part of Osamu Tezuka's renowned tale about a white lion's aspiration to rule the jungle, this movie centers on Leo's young cub, Lune, who becomes intrigued by humans upon finding a music box in an airplane wreckage. Concurrently, a greedy adventurer named Ham Egg leads a group in pursuit of the legendary Moonlight Stones, believed to hold the key to solving an energy crisis. In a quirky twist, two unconventional humans named Dr. Moustache and Lemonade strive to thwart Ham Egg's destructive plans in the jungle. As a devastating virus spreads among the animal inhabitants, Dr. Moustache races to develop an antidote to save them. The narrative crescendos with a perilous expedition up the fabled Mt. Moon as they seek the elusive stones.