Since the 1980s, Ian Redmond has been researching an unusual and endangered elephant population in the Mount Elgon area.
This population, of which the matriarch Kali is a member, consists of savannah elephants that have adapted to living in the mountain forests. They are now isolated after humans took their surrounding habitat away from them. The animals seek out hidden caves at night to chisel mineral-rich volcanic rock off the walls with their tusks, thereby expanding these subterranean salt mines into enormous chambers. This underground behavior is unique among elephants. What is behind this mysterious mining activity?