The setting is the islands off the Dalmatian coast of Yugoslavia, during WW II. The islands are controlled by occupying Italian forces, and a resistence movement of Communists is dedicated to sabotaging and ending the occupation. When a wealthy young man joins the resistence, he falls in love with a woman who turns out to be a spy for the Italians. As a result of his liaison and her activity, they are both executed by a Communist comrade - a previous friend. The comrade is dedicated to the hard-line policies of the resistence, until he himself falls in love with the daughter of a bourgeois landowner on the island - a landowner who has collaborated with the Italians. Neither the Italian occupying army (one officer is shown in an attempted rape scene) nor the resistence fighters are stereotyped forces for good or evil, but all are equally subject to the dehumanizing effects of war.
