Professor Sinigaglia (Marcello Mastroianni), a labor activist on the run from the police in Genoa, hops off a freight train and comes to hide in the neighborhood. There, he runs into a meeting where the undeterred workers discuss the idea of all coming to work an hour late to make their point. The bookish-looking, unassuming Sinigaglia becomes involved, and in a burst of fiery rhetoric persuades the workers to escalate their struggle by not coming to work at all and going on strike instead. Drawing on his own experience, he also helps them to prepare effectively by building up a stock of supplies.