At the very beginning of the World War I, Filip, a Serb and the principal of a gymnasium in a small Serbian town, is summoned urgently to Belgrade to serve in the war effort. He has no one to leave his wife Lea with. She is a young and pretty Slovenian woman, a teacher of rhythmics and dance he met while studying in Western Europe. Azem, an illiterate, patriarchal Albanian, the school custodian, gives Filip his solemn oath, his 'Besa' (in the Albanian tradition: when someone gives their word which must be kept even if they lose their life in the process) that he would look after Lea and see to it that nothing happened to her. Two Europeans, from two entirely different cultures and habits are forced to an awkward cohabitation in the empty school. While the war rages in the background and gets menacingly closer, their interaction develops from hatred, through intolerance, to tolerance and an unusual friendship. Circumstances gradually draw Lea and Azem, a Christian woman and a Muslim man, into a complex forbidden relationship - something like love! More than merely a romantic story, this movie is a paradigm of profound ethnic and class divisions in Europe in the early 20th century which some of them prevail to this day.