Tintin finds a lost briefcase and returns it to the owner Professor Hector Alembick who is a sigillographer an expert on seals (as in the sort used to make state documents official). He shows Tintin his collection of seals including one which belonged to the Syldavian King Ottokar IV. Tintin then discovers that he and Alembick are under surveillance by some strange men. Tintin''s flat is even bombed in an attempt to kill him. Suspecting a Syldavian connection Tintin offers to accompany Alembick to Syldavia via Frankfurt and Prague for research.On the plane Tintin begins to suspect his companion. The Alembick travelling with him doesn''t smoke and doesn''t seem to need the spectacles he wears - to the point that he can make out a pretty pattern made by the sheep in a field that the plane passed over - while the Alembick he first met smoked constantly and had poor eyesight. During a layover Tintin fakes a fall and grabs Alembick''s beard thinking it is false and Alembick is an imposter. However the beard proves to be real and Tintin decides to let the matter drop assuming that Alembick simply gave up smoking and is better at long distances than close-up- but then while flying over Syldavia it is the pilot of the plane who opens a trap door and Tintin drops out landing in a haywagon.