Mantas eat plankton, not fish. So why would oceanic manta rays, among the largest of the species, make an annual pilgrimage from the waters of Mozambique all the way to the coast of South Africa to attend the sardine run, the world's largest migration of marine animals? Follow dedicated manta researchers as they work tirelessly to discover the secrets of one of the ocean's most mysterious and majestic dwellers. They might even discover new species along the way.

The coastal waters of Mozambique are the domain of giants, from visiting humpbacks to resident whale sharks. But the tiniest species also play a big role. Brightly colored slugs known as nudibranchs inhabit shallow reefs, estuaries, and mangroves. Of the 200 species here, 90% are newly discovered. Follow the research team as they navigate fickle tides and indiscriminate fishing practices to protect the marine giants of Mozambique--and the tiny creatures that live in their shadow.

To a marine biologist, any attempt at mapping an oceanic food chain begins and ends with plankton, from tiny bacterial algae to soft-bodied animals such as jellyfish. These microscopic miracles are responsible for producing two-thirds of atmospheric oxygen. Their place at the bottom of the chain has the greatest impact on marine life, whether they're providing nourishment for filter-feeders such as sardines and manta rays or predators like dolphins and sharks.