In a jungle in Africa right on the equator there was a white lion, Panja, who was called the "Emperor of the Jungle." But Panja is killed by a hunter. His wife, the Queen of Jungle, who has been caught by the hunter, gives birth to the son of Panja on a ship bringing them to a zoo. She names her son "Leo" and has him escape from the ship, saying, "Go back to Africa and become the successor of your father." Then a storm comes and the ship is overturned, and sinks with the Queen on it. Leo is washed up on the beach of a port town in the Arabian Peninsula, not Africa. This is where Leo's long adventure begins.

Volumes 1-3 of the Osamu Tezuka Complete Works