In the first half of the 20th century, the young nun Pascalina is sent to Munich, to be the housekeeper of the Nuntius Eugenio Pacelli - and for Pascalina this turns out to be a fateful encounter. She becomes his assistant private secretary and personal adviser. Soon other nuns accuse her of also spending time in his bedroom. Pascalina is called back to the convent, advised to repent and to renew her vows. Deeply offended, she refuses to do so. With the help of Cardinal Faulhaber she is able to follow Pacelli to Rome. Here Pascalina comes up against considerable opposition from his new right-hand man, Monsignore Wilson. However, he is unable to prevent a meeting between Pascalina and Pacelli. Before long her notes on a draft agreement land on the desk of Pope Pius XI, who is extremely impressed by the sharp mind this nun clearly possesses. He gives her permission to live within the walls of the Vatican - the first time a woman has been allowed to do so – and Pascalina’ life gets even more difficult.