The Fishy Doubloon Caper.While exploring a shipwreck off the coast of Ecuador, Carmen stumbles upon hidden treasure in the form of an old gold coin, but her old classmate "El Topo" battles her underwater for it while his partner "Le Chevre" confronts Zack and Ivy. The chase continues to the mainland after a tuna swallows it, gets caught by fishermen and then later put on sale at a fish auction. Carmen meets with local archaeologist Dr. Pilar Marquez (Carla Tassara), who tells Carmen of the historical value of the Ecuadorian doubloon back in the 19th century, prompting Carmen to find it and return it to the doctor...