It portrays the Swiss Army fighting against an unnamed, unseen enemy, using heavy weapons such as flamethrowers, artillery, tanks and bomber aircraft.
After the enemy is repelled, the film closes with idyllic shots of beautiful Swiss landscapes.
The film was a popular success in Switzerland, attracting more than four million viewers (about two thirds of the country's population).
The project, led by Major General Gustav Däniker and by Rudolf Farner, a powerful advertising executive in civilian life, was however controversial because of its exorbitant CHF 1 million production cost, concerns about military secrecy and the use of foreign rather than Swiss creative staff.
In a slightly adapted form, the film was also shown abroad under the English title Fortress of Peace.