Long ago in the age of dinosaurs, a volcano in eastern China erupted and buried a host of strange creatures in ash, creating exquisite fossils that preserved a big surprise—many dinosaurs were covered in feathers. In The Four-Winged Dinosaur, NOVA investigates the most bizarre of these feathered dinosaurs, which has rekindled a fierce, decades-long debate over the origin of bird flight.

The central character in this drama is a strange little dinosaur with wings on its legs as well as its arms. The pigeon-sized Microraptor is the smallest adult dinosaur ever found, perhaps the first known tree-dweller. But could it really fly? NOVA assembles a team of top paleontologists, aeronautical engineers, and paleo-artists to reconstruct Microraptor and build a sophisticated model for a wind tunnel experiment. The results have surprising implications for long-accepted ideas about how winged flight began.