Lithuanian Karin (Ingrid Bergman) flees her war-ravaged home country and winds up in Italy, where she's sent to an internment camp. There, she meets Antonio (Mario Vitale), a POW who's just been freed. They enjoy a brief romance, punctuated by Antonio's marriage proposal, and Karin, seeing her chance to escape the camp, accepts. But Antonio takes her back to Stromboli, the volcanic island he lives on, and Karin struggles with a language barrier, brutal living conditions and her outsider status.