Once again Professor Calculus gets himself kidnapped, this time by the unscrupulous Bordurians. Tintin, Snowy and the Captain are soon on the trail again to rescue the Professor and save his fantastic invention. Spies are everywhere, and Calculus lies deep in the fortress of Bakhine. If one book had to be selected as Herge's masterwork of the classic strip cartoon, it surely would be The Calculus Affair, with richness of subject, speed of action, skill in artwork and dialogue.