The story follows the Plants as they use Torchwood's new "dinosaur claw machine" to retrieve dinosaur eggs from the Triassic period.

After an egg hatches into a dinosaur that Bonk Choy initially rejects, the Plants accidentally stumble upon a secret Zombie base.

They are subsequently thrown into a time hole, transporting them back to the Triassic era where they must navigate dangers from the Saltopus and befriending a Mussaurus to find their way home and save their town.