Clayton and the lovable, comical characters of Grampy, Mom, and Austin along with the smartest dog ever, Daisy, are off on another adventure aboard the houseboat, the Granny Rose. This time the crew is traveling from Mobile, Alabama to Destin, Florida on the Intracoastal Waterway.On this journey, there are visits to the Battleship Park in Mobile where Clayton and Austin meet their phobias of height and close spaces head-on as they tour the retired United States Navy ships of the USS Alabama and the USS Drum. Will the boys consider new career paths after the tour?A trip to Dauphin Island finds the group facing the "bride ghost," alligators, stingrays, and even goats in trees. Daisy faces her fears by jumping into Clayton's lap and barking continuously as a mysterious object keeps resurfacing out of the waters of Mobile Bay and the Intracoastal Waterway. Could it be the yellow submarine of Sneaky Pete?As the group proceeds down the waterway, visits to Perdido Key and the Naval Museum in Pensacola, bring more adventures, with the viewing of the mysterious object continuing to frighten Daisy. Why can't Grampy see the object protruding out of water?In Destin, the group meets up with reoccurring characters of Sydney and Camryn, and their families for a suspenseful ride aboard a real submarine. Does the shipwreck bring fame and fortune to them? Will the boys and girls find "real treasure?"