You are in the wetlands of Europe, 125 million years ago.

The damp morning air of the early Cretaceous floodplain hung heavy, smelling of crushed ferns and wet mud. You were crouched near the edge of a cluster of horsetails, when a sudden, rustling silence fell over the immediate undergrowth.

Twenty feet away, a flash of dull green and pale yellow appeared, followed by another, and another. It was a flock—a herd, really—of Hypsilophodon. They were fast. Almost bird-like in their movements, yet scaly, moving with a jerky, nervous energy.

One stopped, snapping its pointed beak in your direction while balancing on its long, rigid tail. Its eyes, large and intelligent, seemed to lock onto yours, assessing if you are a threat. The rest of the flock, perhaps a dozen others, continued to forage, using their sharp teeth to nip at the fresh plant material with incredible speed.