Students dressed in deep sea helmets travel to the ocean deep in a yellow school-bus submarine. When they get there, they frolic with fish, luminescent squid, and discover an old shipwreck. But when it’s time to return to the submarine bus, one student lingers to take a photo of a treasure chest and falls into a deep ravine. Luckily, the child is entertained by a Plesiosaur - an extinct sea creature - until being retrieved by the teacher.