"Leo the Lion" is the sequel, or second season, to "Kimba the White Lion".
Leo (who is the adult Kimba) and Lea (Kitty) raise their own family, two cubs: a boy (Rune) and a girl (Rukio). At the same time, Leo is intent on keeping his jungle safe from humans. This is in continuation of the deal Kimba made with the humans in the last episode of the first series (“Silvertail, the Renegade”, which was originally titled “The Man-Eating Lion” in Japan). In the Japanese script, Kimba promised to keep his animals separate from humans, and that promise underlies Leo's actions in this series.
One notable thing about the "Leo the Lion" series is that the last two episodes provide an antidote of sorts for the Jungle Emperor Leo movie (1997)--the movie returned to the original manga and told the tear-jerker stories as written in 1950, which quite frankly were bad storytelling. The changes made for "Leo the Lion" vastly improve the story and provide a satisfying ending.
Here are my choices of the top 8 episodes from this series:
Episode 5: “Leo Becomes a Father” (a.k.a. “Rune’s Adventurous Journey”)
Rune and Rukio are born to Leo and Lea. Leo decides that Rune needs some help to be able to handle the life that awaits him. This is a good story, well told. And, of course, the birth of the cubs shapes the course of the rest of the Leo the Lion series.
Episode 6: “The Mighty Gorilla” (a.k.a. “Dwimag the Mighty”)
A peaceful band of gorillas, dependent on a giant gorilla for their safety, are seeking a new home. Rukio gets to shine in this episode, as she befriends the fearsome, and fearful, giant gorilla. I am partial to this episode because it truly stars Rukio, who is so much like Kitty in "Kimba the White Lion".
Episode 10: “Rick the Lycon” (a.k.a. “Lycons Do Not Cry”)
An enemy of Leo’s befriends Rune and Rukio. This episode focuses largely on the two cubs, and the title character has a bit of complexity to him, giving the episode the feel of the best of the Kimba series.
Episode 12: “The Poachers”
This is a very powerful episode, dealing realistically with the harm done by poaching. It is quite violent at times, but overall it’s a powerful, worthwhile story.
Episode 18: “Locomotive Battle”
The obnoxious Bizo, the young elephant, must cooperate with Rune or both of them will die. At this point in the series, Rune is a strong character, and the whole episode is reminiscent of the best of "Kimba".
Episode 19: “The Steel Monster” (a.k.a. “The Stone Fortress”)
Rune gets the idea to build a stone castle as protection against disasters like fires. I admit I have a strange reason for liking this episode: It appeals to me on a technical level. The visual style baffles and fascinates me. This one must have been drawn by an entirely different team of artists. Fan art right on your TV screen! (j/k)
Episode 25: “The Green Plague” (a.k.a. “The Sun Will Rise Again Over the Royal Castle”)
A spotted fever plague sweeps through the jungle, affecting most of the animals. This is one of the two most satisfying episodes of the entire series, especially for the Kimba fan who has seen the Jungle Emperor Leo movie. Here, Tezuka re-writes his own story to great effect.
Episode 26: “The Eternal Mount Moon”
Leo accompanies an expedition to Mt. Moon to search for the moonlight stones, which can solve the world’s energy shortage. Rune stows away with the expedition. This episode follows directly from the previous one, like part 2 of a 2-part story. Again, Tezuka has re-written his original story, providing a much better ending than that seen in the Jungle Emperor Leo movie.