The African elephant is the biggest land mammal on Earth and Botswana is home to more than anywhere else in the world. It’s the setting for a titanic battle. Living at the edge of the Kalahari Desert makes finding enough food a challenge. So every year, thousands of elephants must make the 7,000 mile trek in search of plants that flourish for only a few weeks at a time.  As the dry season takes hold, water becomes even harder to find and elephant mothers, who have timed the birth of their calves with the coming of the rain, run the gauntlet against an increasingly hostile environment.  The elephants use their strength and cunning to survive but they are also shadowed by some of the most ruthless predators on earth – lions.