A vicious shark attack on the isolated Hell's Reef, 200 miles from shore, leaves one person dead and the fate of the other unknown. In a small coastal tourist town, Kaz Fellows and Charlie Brody, long term lovers and owner operators of struggling Pearl Air secure a chance last-minute charter; one last big hire before the wet season closes in and returns them to dull, break-even mail runs. Japanese businessman Joji Minase and his wife Michelle want a trip with all the trimmings; Michelle wants to take her grandfather's ashes back to the reef, the site of a pearling incident years before that claimed many lives. With Benny, their fun-loving cook on board, the group leave the coast and fly to Hell's Reef. On the way, Charlie -- a former Marine Biologist and shark expert, now pilot, reveals he abandoned his career when he was attacked by a shark. A wound on his leg a constant reminder of his lucky escape. At Hell's Reef all is wonderful, and after an isolated walk along the lagoon shore, Kaz informs Charlie she is pregnant and together they start to make plans for the future. Their euphoria is interrupted by an agitated Benny. A clearly distressed Michelle and upset Joji direct Charlie and Kaz to investigate a horrific sight the mangled torso of a man, with very some very distinguishable and familiar bite marks. Charlie quickly confirms Kaz's suspicions. Shark! Galvanised into action, the group, under protest from Joji, embark on an aerial recon to see if they can find any other people or a boat in trouble. Towards the end of their search, they find a slowly sinking, upturned yacht. With no survivors visible, it is left to Benny to undertake a perilous dive of the wreck. He finds no survivors. With nothing else to be done, they quickly prepare to leave. As Benny stows equipment in the hold, all are taken by complete surprise, when an unprovoked attack destroys their plane. Benny is flung into the water and hastily scrambles to get back to safety. The plane is unserviceable. The five survivors have no choice. With the seaplane sinking; they abandon it and take to a life raft. So, begins a terrifying journey of survival. The current is swift and with the paddles they could make land within 20 hours if they were left alone. But that's not going to happen! They are being hunted by an underwater monster hell bent on killing them.