Patchi is the smallest of a litter of pachyrhinosaurs, herbivorous dinosaurs that lived in North America during the Late Cretaceous about 70 million years ago. Son of Bulldust, the herd leader, and brother of the proud Scowler, he tries to follow in his father's footsteps. But when Bulldust is killed during migration southwards, the two brothers, together with Juniper, are separated from the rest of the herd. Alone in the forest, they begin their journey homewards. Based on the six-part BBC documentary series broadcast in 1999.