The actor finds himself transported back to a huge forest 68 million years ago in the late Cretaceous period, home to deadly predator Tyrannosaurus rex. With the help of expert Dr David Hone, Stephen observes a T-rex on the rampage, crunching up huge corpses and stalking a herd of triceratops, and they also encounter a giant flying reptile known as quetzalcoatlus. which stood taller than a giraffe and had the wingspan of a light aircraft.