Tourists flock to the reef to enjoy the perfect weather, and the humpback whales are here to give birth. On the most protected island in Australia, 20,000 green sea turtles return to the biggest reptilian breeding colony on Earth. The approach of the wet season brings an explosion of life on the reef as corals spawn, sea birds nest and turtle hatchlings erupt over the beaches in the thousands.  Like a great alien spaceship, the manta ray comes swooping in, a gentle plankton feeding giant up to seven meters wide and weighing as much as two tons.  Soon torrential rain and severe storms will close in, bringing change and upheaval to the delicate ecosystem.