 In 1930, young Gabrielle Van der Mal enters a convent in her native Belgium to become a nun. Almost immediately she has difficulty adjusting to the cloistered life, and its vows of poverty, chastity, and obedience. She doubts her own ability, even as she takes her final vows. Gabrielle, now called Sister Luke, excels in her medical studies and dreams of serving in the Belgian Congo. When she is asked by the Reverend Mother to fail her exams on purpose to show humility, she cannot bring herself to do so. However, despite her excellent score she is not sent to the Congo, but to a sanitarium in Brussels.