This one sneaks up on you, because it opens as a comfort watch and then quietly asks what a lion is even for. Tezuka's Leo gets rebooted into the 21st century as a cub born inside "Eternal Earth," a corporate-built neo-jungle the UN signed off on after humans wrecked the real one, and the horror isn't cruelty, it's convenience. Every animal is safe, fed, managed, and Leo grows up breezy and useless because nothing in a nature preserve ever requires courage. Hanging Panja's name over him is the cruelest touch: a son measured against a father who lived when the wild was actually wild. It's a single special, so it moves like a fable rather than an arc, and it lands the way old Tezuka always did, by making the sweet thing hurt. Bravery you never had to learn is the sharpest thing here.

Leo grows up in an artificial jungle that a private company builds for the United Nations after relentless environmental destruction, a preserve where every wild animal must now live. As the son of the great Jungle Emperor Panja, he drifts through an easy, carefree life while the other animals mock him as a coward. Leo vows that one day he will match his father. His story begins when he meets Kenichi, the son of the company's CEO, who is sure the neo-jungle is a great success and who can understand what animals say.