Beneath the forested flanks of an extinct volcano lies a cave with a mysterious secret. Kitum Cave on the slopes of Mt Elgon in Kenya is the only place on earth where elephants regularly venture deep underground. Driven by cravings for salt, these elephants are forced to make the dangerous venture into the cave. Humans have been drawn to Kitum Cave over thousand of years, originally to harvest salt, but more recently to slaughter elephants, leading to local rangers Daniel and Mike being assigned to protect the survivors