It was supposed to be just an ordinary school day. Will, Iris, and Wenko are waiting for the school bus when they are suddenly beamed away by a robot. Unwillingly, they embark on a time travel adventure that takes them 80 million years into the past. To their astonishment—and to Wenko's excitement—they land in the world of prehistoric giants. There, they meet the eccentric Professor Mercury, who has chosen them for a special mission: they are to help him find the best pet of the Cretaceous period.