All airplane landings are not the same, especially those that end in a crash. Tintin, even by chance, when passing through such a fall, has the luck to enter a new adventure. A mental hospital - a showcase and Doctor Miller seem to be involved in the strange cargoes falling from the sky. The answer will be found in the ruins of Ben More Castle on the black island, where the beast that is said to live there is a threat to anyone who approaches. But the only thing the tower seems to hide is a well-organized counterfeiting operation that sees its end from the moment Tintin set foot on the mysterious island.