A deranged alchemist named Cortez discovers a potion that restores youth, but it requires the tail spikes from stegosauruses, which he is systematically hunting and killing. While investigating the dinosauricides, Karl and Marion have a run-in with the Outsiders.

Crop-harvesting dinosaurs are infected by a virus, and Le Sage has stolen the only medicinal plant that can help.

Frank creates a car but when it begins to pollute Dinotopia, Mayor Waldo bans it. Frank, out of revenge, runs for mayor and wins, and allows the car to continue. However Frank soon learns the error of his ways, and resigns, allowing Waldo to return to his job.

Karl must learn some lessons in love, when a toad, the Wartosa Vulgaris, sends him into a time loop. Stuck in time, he has to keep reliving the same passionate moment with Marion until he gets it right.