One fateful night they are summoned by an unknown alien intelligence who tells them that mankind is losing its empathy, and, to teach them a lesson about life, death, and the fall of species, said alien intelligence transports the kids to Earth's past and leaves them right in the Mesozoic era, the time when dinosaurs were the supreme rulers of the Earth. Here, the trio has a series of adventures and misadventures, like befriending a baby Triceratops, trying to escape from a dangerous Tyrannosaurus rex, witnessing the Cretaceous extinction and rise of the mammals, and discovering why it is important for humans to protect Earth before it's too late.
As mentioned above, the film is very poorly-known, and only a few home releases are known. It can be watched for free online, but is usually found in a foreign language, like Spanish.
- Alas, Poor Villain: The Tyrannosaurus eventually gets speared to death by the Neanderthals, though this becomes sorrowful considering it's the Last of Its Kind.
- All Animals Are Dogs: The Triceratops hatchlings utter puppy-like squeals and coos.
- Anachronism Stew: Despite being set in the Cretaceous, dinosaurs and other reptiles from the Triassic and Jurassic periods appear as well. The most jarring example is the cameo of the pelycosaurian synapsid Edaphosaurus, which was already extinct by the time the earliest dinosaurs showed up. And then there's the Ice Age occurring right at the beginning of the Cenozoic era, rather than millions of years later in the Pleistocene.
- An Aesop: A green one, to be exact. Mankind must learn to take good care of Earth and use its natural resources with balance, for no species lasts forever.
- Aquatic Sauropods: Both of the film's sauropods, Brontosaurus and Brachiosaurus, are only ever shown in water.
- Art Shift: The film starts with live-action scenes of modern Japan with anime-drawn pictures of dinosaurs constantly popping up, then switches to animation. At the end, there's a showcase of dino skeletons exposed in museums to symbolize their ultimate downfall.
- Big Bad: The Tyrannosaurus that constantly harasses the group.
- Dub Name Change: The Triceratops hatchling befriended by the kids is named "Zhu" in both the original and most dubbed releases, but the Mexican Spanish version changes his name to "Papapulis" and the English version calls him "Babypuss".
- Dumb Dinos: Averted, which is commendable as the anime was made recently after the Dinosaur Renaissance had set off. Zhu the Triceratops shows awareness of his surroundings and deliberately sacrifices himself to keep the Tyrannosaurus away from the humans. Unfortunately for the protagonists, the main Tyrannosaurus villain also has signs of intelligence despite being a bloodthirsty predator, as it chases after the heroes out of vengeance for damaging its eye. The other dinos don't seem to be particularly dumb (they even, quite humorously, react painfully to a battle between two male Pachycephalosaurus).
- Eats Babies: The Tyrannosaurus devours all but one of the baby Triceratops that the kids find.
- Expy: Remi bears a strong resemblance to Francoise Arnoul from Cyborg 009.
- Eye Scream: Chobi throws a sharpened stick into the Tyrannosaurus's left eye, gouging it out. At the end of the film, as the Neanderthals spear the T. rex to death, one of the spears strikes and destroys his only remaining eye.
- Family-Unfriendly Violence: This is a very graphic animated film, considering its target audience. The Tyrannosaurus gets gored repeatedly, and several other dinosaurs, including babies, fall to his appetite.
- Giant Animal Worship: The Neanderthals worship the Tyrannosaurus as a deity and make offerings of human sacrifices to it. It takes Chobi standing up to it to finally convince them to try fighting back against the T. rex. It's not unlike Odo from the prehistoric chapter of Live A Live.
- Headbutting Pachy: A pair of of Pachycephalosaurus are shown to be headbutting each other so hard that it not only gets the attention of other dinosaurs, but scares them too. Not the Tyrannosaurus rex though, he came for dinner.
- Heroic Sacrifice: Zhu the Triceratops pushes the T. rex over a cliff, deliberately plummeting down with it, to keep him away from the humans.
- Last of His Kind: The Tyrannosaurus is this by the end.
- Mama Bear: The mother Triceratops fights the Tyrannosaurus for attacking her last remaining young. Sadly, she doesn't win.
- Non-Human Sidekick: The baby Triceratops, later named "Zhu", whom Chobi befriends, imprinting on them as his parents. His brothers and sisters did the same, but the Tyrannosaurus has other ideas...
- Stock Sound Effects: The Tyrannosaurus has the classic showa Godzilla and Gamera roars.
- Super-Persistent Predator: The T. rex shows up everywhere the trio go, even somehow travelling through time all the way to the Stone Age. It's actually pursuing them to get revenge, as they had taken out its eye and Zhu nearly killed it.
- Terrifying Tyrannosaur: The film's main antagonist is a Tyrannosaurus rex, portrayed as the most dangerous of all dinosaurs.
- Twinkle in the Eye: The Tyrannosaurus does this frequently.