Five young people meeet in Senegal on a scuba diving expedition. There are taken to the diving area in an old boat. When an accident makes the engine explode, their vessel sinks and the group are left floating in the middle of the ocean. Their spirits lift up when they see a merchant ship. Just as they are about to ask for help to come abroard, they witness a gruesome murder. No longer daring to draw the attention of the crew, they manage to secretly board the boat and hide. If they can stay out of the sight until the next port, they'll be able to report what they've just seen.