Book is in French While his big brother Arnaud sulks, Loïc, with a happy heart, plays in the snow. Suddenly, a storm of large black clouds falls on them and sucks Arnaud into the sky. Loïc wants to seek help from adults. But Portagnhe the mountain dragon appears. Portagne knows how to do it. We must pursue Captain Baboune, who has just kidnapped Arnaud on his strange flying boat. Indeed, the Black Star of Baboune is fueled by the quarrels and grumblings of the captive child sailors. To free Arnaud, Loïc must convince the crew to mutiny...