
The Calculus Affair
By HergeIn The Calculus Affair, Tintin and Captain Haddock must protect Professor Calculus from evil spies who are after his latest and greatest invention - an ultrasonic device that could change the world. The plot thickens as Tintin and Haddock realize every one of their moves is being watched by a shadowy web of espionage ready for action at any given moment.