Oreste Jacovacci from Rome and Giovanni Busacca from Milan meet each other during the call to arms at the start of World War I. Although completely different in character, they are united in their lack of idealism and their desire to avoid any danger and get out of the war unscathed. They and a varied group of civilians and fellow soldiers (including the prostitute Costantina, played by Silvana Mangano) go through many ups and downs during their training, battles and rare moments of leave. They are considered "inefficient" due to their limited military valour and so are made message-runners to the staff, a very dangerous job. Having succeeded in their mission, a sudden change in a which-side-hold-which-trench situation leaves them in enemy territory, where they are captured by the Austrians wearing Austrian uniforms they had found in a barn.