The Deadly Past

Suddenly there are creatures from the ancient past in Spooksville. Huge meat-eating lizards attacking people in their cars. Flying reptiles swooping down and lifting kids away. But where have these dinosaurs come from? Adam and his friends discover that a huge doorway has been created between present-day Spooksville and sixty million years ago. It is through this doorway that the dinosaurs are attacking. But who created this doorway?
How can it be closed before all of Spooksville is destroyed?