Africa's wild coast, a vast, seemingly empty expanse of ocean. But once a year, the inhabitants along Africa's eastern shore prepare for an event like no other on Earth - the Sardine Run. Millions of tiny fish amass for an annual migration, turning the waters dark as they swarm in an ever-tightening frenzy. For the predators, the feast has begun. Driven by instinct, the unstoppable slick of fish is followed by one of the most significant gatherings of predators all here for one thing - to make the most of this seasonal time of plenty. The result is an underwater spectacle like nothing else on Earth, the Ultimate Sardine Run.