Caught on tape in Africa's wild Serengeti is a stunning act of violence between two top predators. Three cheetahs are brutally attacked by two male lions - the first time an attack like this has ever been filmed. Now, filmmaker Leo Kuenkel, who witnessed the attack, is trying to make sense of it. Was this a once-in-a-lifetime "perfect storm" event? Or do these iconic African cats have a deep-set, sinister reason to fight to the death?