In the heart of the Pacific Ocean the sea around the Tuamotu islands is coursing with life. Hundreds of shards cruise though underwater canyons above a seabed carpeted with coral. Scientists often cite the relationship between healthy reefs and top predators, but they don't really know how it works. Time and again as top predators disappear entire ecosystems below them fail. This film will find out why corals need sharks, just as much as sharks need corals. It uncovers how two of the most threatened groups of animals in the ocean are truly dependent on one another, and therefore must be protected if either of them are to survive into the future.
