It all starts when Tintin tries to help a plane in trouble. The pilots shoot at him and run away. Tintin is hospitalized but starts his investigations as soon as he feels a little better. One day, Pushchov, who is the leader of a gang of forgerers and the person behind the plane incident, recognizes Tintin at a train station. Be boards the same train to try to get Tintin arrested for assault and burglary. After a few times of Thompson twins loosing Tintin and Tintin escaping them, Tintin finds a crashed plane on his way to Eastdown. He looks around for clues and finds a flying jacket with a few pieces of papers in its pocket, from which he figures out his next step. His investigation leads him to Dr. Müller's house where he gets caught in a man-trap. Müller tries to kill him which results in a fight, in the course of which the house catches fire. Müller escapes and Tintin is rescued by the firemen.

Strange events at Marlin Spike Hall and the kidnapping of Professor Calculus send Tintin, Snowy and Captain Haddock on a dangerous rescue mission.