India's famous "unity in diversity." Using all the tools available to the historical detective -- from DNA to climate science, oral lore, ancient manuscripts, archaeology and exploration of the living cultures of the subcontinent -- Wood takes viewers from the tropical heat of South India to the Ganges plain and from Pakistan and the Khyber Pass out to Turkmenistan, where dramatic archaeological discoveries are changing the view of the migrations that have helped fashion Indian identity. The episode begins long before recorded history, with the first human journey out of Africa. In the tropical backwaters of Kerala, Wood finds survivals of human sounds and rituals from a time before language. In Tamil Nadu, the latest DNA research takes him to a village where everyone still bears the genetic imprint of those first "beachcombing incomers" -- the "first Indians" who went on to populate the rest of the world, excluding Africa. Wood investigates India's "first civilization" -- the lost cities of Harappa and Mohenjo-Daro in today's Pakistan -- and the mystery of their collapse, which Wood speculates may have been due to massive and far-reaching climate change. He also covers the "Age of Heroes" in the time of the great Indian epic, the Mahabharata. Throughout, this colorful and exciting film is full of the sights, sounds and people of today's India. Wood ends the episode among a vast crowd of pilgrims at the festival of Holi in Mathura in northern India. Covered from head to foot in colored powder, he tells his viewers, "This is just the beginning!"