Doctor Natureza needs help to clean up the ocean. Indeed, a large sheet of plastic floats on the water and endangers the flora and fauna. Grisù, accompanied by Stella, boards the « laboratory boat » to help Doctor Natureza vacuum up the waste with the machine she has developed. But throughout the process, Grisù burns the pumping engine. They can't vacuum the ocean anymore. Fortunately, Grisù has the idea of using all the waste that lies around them and Natureza's bicycle to design a new – and ecological- device that finally allows them to achieve the mission. Because, as firefighter, Grisù never gives up!
