Smeraldo is to sail to the famous pirate Red Hair Anna's shipwreck to retrieve its treasure chest. Grisù, accompanied by Stella, goes with Smeraldo to operate his boat crane and haul the treasure, while Smeraldo is in his submarine. Unfortunately, the young dragon unwittingly breaks the professor's glasses and has to pilot the submarine all by himself. He finds the treasure but also encounters a giant and playful octopus. Grisù, surprised by the animal, burns the rope and the treasure sinks back into the sea. Everything seems lost, but a firefighter never gives up! Using a giant air bubble, Grisù manages to bring the treasure up again and saves the mission.
