Angela and Robert have been married for ten years and make a perfect couple. They are madly in love with each other, give each other plenty of space and support each other in everyday life. This idyll is put to the test when Robert's girlfriend Claudia moves in with the couple and Angela falls in love with another man. According to a mutual agreement between Angela and Robert, anything goes if one of them breaks their promise never to leave the other.

故事发生在1942年的德国，在穿越西西里亚的火车上，罗莎（伊丽莎白·特里斯纳 Elisabeth Trissenaar 饰）和自己的丈夫失散了，幸运的是，她得到了当地的一名农场主里昂（阿明·缪勒-斯塔尔 Armin Mueller-Stahl 饰）的救治和收留，里昂将罗莎藏在了自己家的地窖里。
里昂是一名非常虔诚的基督教徒，早就决定将自己的全部都奉献给上帝，然而，人性是无法抑制的，罗莎的出现让里昂第一次感受到了体内欲望的灼烧。里昂希望能够得到罗莎，但是罗莎提出了一个交换的条件，她要求里昂为当地落难的犹太人提供庇护。交易就这样达成了，但感情和爱真的能够像生意一般简单和利落吗？