Father Adrien, by taking the vow of silence, constant prayer, and chastity, gains entrance to the Trappist Monastery of Notre Dame d'Afrique in Algeria. While clearing a tree from the monastery wall, he accidentally knocks a young girl unconscious, and on reviving she intrigues him into an embrace; his sin is reported by an onlooker and he is forced to undergo penance; but the beauty of woman and the outside world entice him to renounce his vows and escape into the desert, resuming his secular name, Androvsky. En route to the oasis of Beni-Mora, he encounters Domini Enfilden, a deeply religious girl, and rescues her from a Bedouin riot. At a party in the gardens of Count Anteoni, she notes his fear of the cross and of priests, and he breaks away, frightened by a sand-diviner. In face of warnings, Domini marries Androvsky, and they go into the desert; Anteoni realizes his true identity but agrees to keep it secret. During a sandstorm, Androvsky confesses to having broken his vows and returns to the monastery to do penance. Years later, Domini sings to their son a song of freed Bedouin slaves: "Only God and I know what is in my heart."