In this episode of The Global Reef Expedition, the Living Oceans Foundation team settles in for a month on the GBR, the largest reef in the world. One of them is studying sharks, and in a flashback we visit French Polynesia, where sharks abound and the team films natural shark feeding behaviors for the first time ever. Back on the GBR, the scientists explore the northern Reef, until recently the healthiest part. The program concludes with new footage of the 2016 bleaching and severe die-off among these corals.