After her last adventure, Tobari finds herself at the beach but she isn't there to catch a few rays. A mysterious voice calls out to Tobari, asking for her help. With nothing else to go by, Tobari journeys to the sea to help this mysterious person. Her journey won't be easy as she'll be challenged by the denizens of the sea who aren't keen to let a surface dweller pass so easily. But what are the sea dwellers trying to accomplish? And who is it that calls out to Tobari?