A talking hippo in a neon-green "P" shirt tries to stay inconspicuous. The absurdity is the point, and the movie commits to it completely, treating a ridiculous premise with enough genuine heart that you're rooting for Potomas to escape capture, not laughing at him. Kids who stumble onto this discover something 80s anime rarely does: pure, uncomplicated adventure where the hero's biggest handicap is his own visibility.
Potomas is a hippo with an extraordinary ability: he can talk like any human. Only two kids, Maki and Toshi, know his secret, and they've sworn to keep it quiet. Potomas tries to blend in wearing nothing but a bright green shirt with a giant "P" on the front, which he genuinely believes makes him inconspicuous. Everything unravels when Potomas saves a drowning child and forgets himself, speaking directly to the kid in perfect human speech. Word spreads fast. Soon the whole city buzzes with talk of a talking hippo, and Potomas finds himself hunted by curious onlookers, journalists, and who knows what else. What started as a quiet life among humans becomes a desperate game of hide-and-seek. Maki and Toshi become his unlikely protectors, helping him evade capture while searching for safety. This is a lighthearted adventure that plays with the absurdity of a secret that can't stay secret, mixing gentle humor with genuine stakes. It's the kind of story that appeals to anyone who remembers the magic of childhood friendships and protecting someone you care about, no matter how unusual they might be.