Imagine a moment from the age of dinosaurs frozen in time: primitive birds, bees, insects, early mammals, the first known flowering plants and of course, dinosaurs, all exquisitely preserved in fine-grained fossils from China's Liaoning Province. Volcanic eruptions killed and buried victims quickly in this dinosaur Pompeii, capturing soft, fragile features not normally preserved in fossils - notably the feathers on animals that had never been known to have them before. Now, with state-of-the-art animation to bring this lost world to life, NOVA investigates the mysterious feathered dinosaurs that are challenging old ideas about 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? Is it the key to understanding the origin of flight or merely an evolutionary dead end unrelated to the ancestry of birds? To help solve the riddle, 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.