You are in the forests of South America, 235 million years ago.

The air in the early Triassic is hot and dry, heavy with the scent of volcanic ash and dusty conifers. While crossing a rocky ledge in Argentina, you stop, hearing a rapid rustling in the sparse, pale ferns.

A movement—barely a foot-long creature sprinting on two, slender, hind legs. It is a Marasuchus.

It pauses, turning its head with bird-like precision. Large eyes lock onto you for a split second, long, curved neck arched alertly. A light covering of proto-feathers—more like fine, stiff hairs or downy fibers than modern flight feathers—coated its back and long, tapering tail, offering insulation rather than flight. It doesn't look like a slow reptile; its posture is light, delicate, and built for speed.