It's the smallest and most mysterious army in the world: the Swiss Guard. The film follows these men of faith and combat, from their recruitment in Switzerland to their military training in the heart of the Vatican. Made up of 150 men, this elite corps lives in barracks in the center of Vatican City. All must be Swiss citizens and devout Catholics. They have all sworn to fight to the death to protect their faith and the Holy Father. They are heirs to a 500-year-old tradition in which the Pope's protection and security were ensured by Swiss mercenaries. Trained in the use of both halberds and semi-automatic rifles, the Swiss Guards form a unique army. But who are they really? What motivates these young men to join this military and religious body? A dive into a world normally closed to the cameras.

• Documentary