 Learning that Müller 's plane had crashed off the coast of Kiltoch , a Scottish coastal village , Tintin travels there to continue his investigation . At Kiltoch , an old man tells him the story of Black Island — an island off the coast where a " ferocious beast " kills any visitors . Tintin and Snowy travel to the island , where they find that the " beast " is a trained gorilla named Ranko . They further discover that the forgers are using the island as their base , and radio the police for help . Although the criminals attempt to capture Tintin , the police arrive and arrest the criminals , with Ranko going to a zoo . 
