El siglo XX, ¡qué progreso!

Professor Bacterio has invented a device capable of sending people to the 21st century and back. The aunt. he wants to send some agent to go through the 21st century so that when he returns he tells what he has seen. The Superintendent decides that Mortadelo and Filemón will be in charge of testing the invention. By mistake Bacterio and Ofelia leave with them. But the invention goes wrong and instead of going to the 21st century they go to the beginning of the 20th century. Mortadelo, Filemón, Ofelia and Bacterio will travel throughout the 20th century where they will live adventures and comic situations, such as the sinking of the Titanic, the World Wars or the Spanish Civil War. They are finally rescued by the Super, who, angry at the mistake of the Bacterio's invention, sends him to work in an office in the sewers.