S1, E5: The Great Flood in the Okavango turns 4000 square miles of arid plains into a beautiful wetland. Elephant mothers guide their families on an epic trek across the harsh Kalahari desert towards it, using their trunks to siphon fresh water from stagnant pools along the way. Hippos battle for territory, as the magical water draws in thousands of buffalo and birds, and vast clouds of dragonflies. As the flood finally reaches its peak, elephants and buffalo, near the end of their epic trek across the desert, face the final gauntlet of a hungry pride of lions.