Solemn Promise 2009 one on netflix

At the beginning of the World War I, Filip, a Serbian school director in the Serbian province, has been asked to immediately go to Belgrade to get war schedule. His wife Lea, Slovene, with no one to leave because the two of them recently arrived in the small town and no one really knows them. Azem, an Albanian, school attendance, gives Filip a promise (Besa) to watch the Lea and that nothing will happen. Lea and Azem, are forced to live together in an abandoned school. Their relationship changes during the time.