A multitude of guests and scientists join William Shatner to explore everything from human origins to groundbreaking archaeological finds, new understandings of the cosmos, and the profound possibility that humans are not alone in the universe. Ancient Aliens examines 75 million years of the most credible alien evidence here on Earth: from the age of the dinosaurs, to ancient Egypt, to the skies over the western desert in the present day US, ancient cave drawings of strange creatures, an asphalt-like substance in an Egyptian pyramid made from the remains of unidentified creatures, continued mass sightings in the USA.