Join scientists as they hunt for fossils that will offer new clues in a 400 million-year-old mystery.

According to the theory of evolution, all four-limbed animals- from dinosaurs to human beings- descend from a single creature. The search for this animal, the missing link in the evolutionary process, is considered to be the Holy Grail of paleontology.

NOVA joins several scientific detectives as they travel to South Africa, Latvia, Greenland, and Pennsylvania in a remarkable search for fossilized remains that may reveal new clues about the nature and identity of this mysterious part fish and part-four legged animal.

See the rare coelacanth (‘see-la-cant’), a fish believed to be extinct for 76 million years but found in the Indian Ocean in the 1930s. Dig through Pennsylvania’s Red Hills and learn more about the struggle for life and limb over 400 million years ago. Witness the crucial rediscovery of a tiny fossilized jawbone that went overlooked for decades in a dusty museum drawer. And see how new evidence is challenging long-held theories about the first creatures to leave the water and walk on land.