Based on the novel by A. J. Cronin, a Scottish man has an atheist friend and becomes a missionary in China where he works with a Chinese man and three nuns to help the Chinese people even though his superiors are critical of his work.
In September 1938 the priest Francis Chisholm (Gregory Peck) has returned to his earlier home in Scotland and talks with the Monsignor (Cedric Hardwicke) at Tweedside about retiring. The aged Francis does not want to retire. The Monsignor mentions some reports about Francis that question his work. Francis asks to see the bishop, and the Monsignor says goodnight and goes upstairs. In the bedroom the Monsignor begins reading the journal written by Francis.
The boy Francis Chisholm (Roddy McDowall) is eating breakfast with his father Alec Chisholm (Dennis Hoey) and his mother (Ruth Nelson). His father says goodbye and goes out. His mother tells Francis they are Catholics and that some people hate and fear them.
At night in the rain Alec Chisholm is beat up by men who say they warned him to stay away from the town. At home Mrs. Chisholm is worried and goes out to look for her husband. The housekeeper suggests that Francis go too. Mrs. Chisholm finds Alec and helps him in the rain. While crossing a suspension bridge they are both washed into the river. Francis arrives just in time to see them swept away. Later that night after the bodies were found, Francis comes home with young Nora.
Francis and Nora are taken to be raised by her relatives. Several years have passed when Francis Chisholm (Gregory Peck) says goodbye to grown-up Nora (Jane Ball) as he goes off for his last year of college. He kisses her, and she says he will not come home to her. She says he is going to be a priest. Francis insists he loves her and does not want to be a priest. Nora is jealous of Polly. Nora kisses him as Polly approaches. She asks Francis to write to her. Francis says goodbye to Willie Tulloch (Thomas Mitchell) and gets on the departing train with Angus (Vincent Price).
The next summer Francis reports to Father Hamish MacNabb (Edmund Gwenn) who asks him if he has thought of his future. Francis says he wants to find a vocation and says he got a letter from Polly not to come home this year. He feels something is wrong and he should go there. Hamish asks if he is in love with Nora.
Hamish and Francis go fishing in a stream and catch a fish. At table they have eaten the fish. Francis hears the train’s whistle and says he has to go home. Hamish tells him that Nora has changed and that she had a baby girl. She is very ill and asked that Francis not come to see her. Hamish says he can still catch the train, and Francis leaves.
Francis arrives at night and asks Willie how she is. Willie is a doctor and says that Nora is dead. He suggests they walk outside. Francis goes into the church.
In his journal Francis wrote that he was not successful as a priest. He meets the new bishop who is Hamish. He shares some whiskey with Francis who admits he is a failure. He tries to explain how he was trying to help people. His closest friend is an atheist, and Francis says that Willie is his best friend. Hamish says he is partial to the stray cat and that Francis is like one. Hamish says Francis is inquisitive and is excited about his work. Hamish advises him not to change. He suggests that Francis become a missionary in China. Francis says he will be happy to go. Before he leaves, Hamish gives him an umbrella.
In his journal Francis wrote how different China was when he first came there. Chinese people are on the dock as he arrives. A rich man Mr. Chia (Leonard Strong) disembarks, and Francis has to carry his own luggage. A Chinese man and his wife have come to lead Francis to his new home. The man shows him a ruined building. They say they got money to buy rice; but when the rice ran out, the 400 communicants left. Francis says he cannot pay them any money. Francis says he understands their language, and he does not like “rice Christians.” Francis finds a stable and rents a small room in the city.
Francis and a sign he put up are pelted with rocks. In the stable he writes a letter. Joseph (Benson Fong) arrives and tells him his name. Joseph says he will work, and Francis says he cannot pay him. Joseph says he is a Christian, and he wants to serve him. Joseph brought some food to share.
Francis and Joseph open a crate with supplies for them with a letter from Willie. A sign says “Mission of St. Andrew a Public Dispensary” in Chinese. Francis reprimands Joseph for trying to abduct a convert. An older woman with a little girl comes in and is coughing. Francis gives her something to drink. She came because her child is a female. She wants him to take care of her granddaughter when she dies. Francis says he will accept her because they will have a school when the sisters come. Mr. Chia’s envoy Mr. Pao (Philip Ahn) asks Francis to come help his cousin. Joseph warns Francis he could get in trouble if anything bad happens. Francis asks him to pray for him.
Francis goes with Mr. Pao to an elegant house and finds a boy in bed. He pulls back the cover and finds a mangled arm. He asks for boiling water and a cloth. From his bag he applies a liquid. He tells the boy not to be afraid and uses a cloth and chloroform to make him unconscious. Francis prays and begins to cut. After he is done, Francis cleans up and opens the windows before leaving. He tells Mr. Pao to give him warm soup. Mr. Pao is surprised that he cut into his body. Francis says he had to cut off the corruption in his arm.
Francis returns on another day and finds the boy is better. He treats him again with hot water. Francis says he only needs changing his dressing, but Mr. Pao asks him not to come back. Francis walks out and is angry, but he prays to God.
Joseph gives a doll to little Anna. Mr. Chia calls on Francis and sits down. He says his only son is now well because of Francis. He says he came to become a Christian. Francis asks if he wants to be a Christian. He says that if he becomes a Christian, the entire town will become Christian as well. Francis says he does not believe and that he owes him nothing. Mr. Chia says he is unworthy. He bows and leaves in his sedan chair. Joseph tells Francis he turned down a Mandarin. Mr. Chia comes back and asks Francis if he has walked on the nearby hill. Mr. Chia says he would like to donate that property to his church with water rights and twenty of his workmen. He leaves, and Francis and Joseph run to the hill, followed by Anna. Francis picks her up and quotes a psalm.
The church has been built. Reverend-Mother Maria-Veronica (Rosa Stradner) and the sisters Martha and Clotilde arrive. Francis says he did not expect them until tomorrow. He carries their luggage and shows him the schoolroom. He invites them to dine with him, but Maria asks only for milk and food. They go into their house, and Francis sends a Chinese woman to help them.
That evening Francis looks at his calendar. Joseph comes in and says he has pheasants cooked. Francis goes to see Maria in the schoolroom. He says twenty children will be there in the morning. He asks her to help him in his dispensary, and she says he need only tell her when her hours are. He sees a photo of where she lived in Austria. She asks for freedom of action. Their order is contemplative, and they would like to have privacy. He asks her to be careful about money, and she says her order provides what they need. He asks about holy poverty, and she says it does not require her to beg. He says he will cooperate and goes out. She writes about Francis and notes his boots were not clean. She realizes she is sinning against God. She hopes to learn equality before God.
Francis sees the children praying in the schoolroom. In his house he learns that Maria has hired a couple whom he says are bad and should be sent away. She refuses and says she manages her own work. Joseph tells him someone who is drinking has arrived. Francis goes outside and hugs Willie happily. Maria and Joseph approach, and Francis introduces Willie to them. Francis suggests they all have tea, but Maria says she has to work.
That night at a table Willie tells Francis that Judy may marry some day. Francis asks Joseph why he has a black eye. Joseph says he beat Hosannah Wong for criticizing Francis, who rewards him with a new robe. The two sisters tell Francis that the couple stole their valuables and are gone. Maria comes in. Mr. Chia tells Francis he is going to his summer home. He explains that General Wei and the imperial troops are coming to bombard the city. He advises them to leave and find safety. Francis tells the three sisters about the battle that has started. He gives them instructions to come to the schoolroom. There he sends Joseph to bring people to the mission. He instructs the sisters to handle the supplies. Francis tells Maria they must work together, and she agrees. Francis and Willie climb up a tower to see what is happening to the city which is burning. Francis says he must go there, but Willie disagrees. Francis and Willie walk toward the city as refugees are coming to the mission.
A major is awakened, and Francis asks him for a house to use as a hospital. The major says he cannot spare any of his people. The major says he will take over the imperial judge’s house to use as his hospital. Willie gives instructions to a soldier between treating patients. Willie says they must clear out a section of the town that has dead bodies, or there will be pestilence. Francis is persuaded. The major says the wounded were removed, and he orders his men to set fire to the houses. They use torches, and the fire spreads. Willie asks if hell is worse than this.
At dawn Willie tells dozing Francis that they have been working for six days. Joseph comes in and says the mission is burning. Francis and Willie sees the smoke and try to get there. On the way Willie sees a wounded man and is shot. Francis goes back for him.
Willie is lying in a bed while Francis and Maria pray. Willie asks them not to pray for him. Willie realizes he is about to die, and he still does not believe in God. Maria stands up and leaves. Willie speaks to Francis about his kingdom, but he will not be there. Francis hopes they will meet by chance. Willie loves him for not bullying him into heaven. Willie asks for his hand, and Francis prays.
Francis is in the burned-out church, and Maria looks too. She tells him that she treated some wounded soldiers in their dispensary. Francis says no one can destroy his church because he will build it again. Joseph tells Francis the imperial captain is demanding to talk to him. Francis goes to the door, and the captain gives him requests. He must give them rice and supplies and release all Chinese men so they can join the imperial army. If he refuses, they will be destroyed. Francis says he will need time to comply, and the officer gives him until morning. Francis says he will go to his gun position tonight. Francis goes to the city and asks the major if it is possible to capture the imperial gun. Francis says he has been ordered to go there, and they make a plan.
Before midnight the major tells Francis that he is carrying cans of gasoline and will ignite them with his pistol. Francis must keep away from them. The major orders his men to attack after the fire starts. Francis tells guards that he was instructed to come, and they approach the gun position. The major puts down the bag of cans. The imperial officer comes over, and Francis says he brought tin goods and money. The major moves away and shoots at the bag and the soldiers. Francis picks up the torch and throws it at the bag which explodes.
Francis is laying in a bed. Joseph and the major tell him that thirty of the enemy were blown up. Francis asks how long Christianity will endure such killings.
Angus arrives and is welcomed by Francis. Angus meets the sisters and says he can only stay one night. Angus sees the ruined church. In the house Angus says he is disappointed he cannot celebrate a high mass. Francis says Maria did as he would have. Francis learns that Hamish died, and he grieves. Francis hears his voice. Angus says he invited Maria to celebrate.
That night Angus offers wine to Maria who declines and to Francis who accepts. Angus talks of his accomplishments and the problems Francis is facing. Angus says Francis has the lowest convert rate. Angus advises him to make more of a show, but Francis says the Chinese hate that. Angus says he can lecture on how God chastises his own. Maria says goodnight, and Angus goes with her to talk with her. Joseph confesses his sin to Francis and then drops the bottle of sherry.
The next day Angus in a sedan chair says goodbye. He asks Francis to thank Mr. Chia. Angus says that Francis will build his church.
Maria finds Francis praying in the ruined church. She confesses that she behaved shamefully toward him and apologizes. She says her humiliation is giving her peace. She knew his humility was true, but her compassion was filled with doubt and pain. She describes how the worldly priest was not worthy of him. Francis says they are all children to God maturing.
Ten years later Francis has a bad leg and cannot see very well. He makes candles out of beeswax and gives honey to the children. The new church was built because of the generosity of Maria’s family. He questions a boy and offers him double honey. Maria tells Francis that Joseph is getting married. She tells Francis that an American Methodist mission has come to their city. Francis says he will call upon them.
In a suit Francis goes to welcome the new missionaries. He meets Agnes Fiske (Anne Revere) and Rev. Dr. Wilbur Fiske (James Gleason). They ask if he resents their coming there. He asks why he would do that. Agnes says they have been in China over twenty years. Wilbur says they are from Maine. Francis learns that their son is now in his home town. They met Angus, and Francis calls him “stuffy.” Wilbur offers him tea, and they become friends. They agree to help each other. On the street Mr. Chia tells Francis that he could look with displeasure on the missionaries of the false god. Francis says they serve the same true God he worships. They walk together and chat.
Joseph now has sons who are grown up. Francis is old and grey. Two priests have been sent to replace him, and Sister Mary came from Australia. Maria tells Francis to drink his milk. He is going tomorrow but does not want to leave. Maria says they will miss him so much. He says he has been rereading his journal. He mentions how Angus became a bishop. Francis says he does not have his charm and has only about six friends. Maria says Francis is closer to God than he. Francis writes that he said goodbye to Maria and asks how to do that after knowing each other so well. He quotes Hamish who said, “Let almighty God have his way.” He prays for them, and she gets up slowly and says she will never forget him.
Francis rides in a car, and many Chinese people have come to wish him well. He hears his favorite hymn. He shakes hands with Mr. Chia and says goodbye to Anna and her daughter. Joseph tries to make a speech he has written but drops it. Joseph asks how he could speak like that. He says they all have memories of his love and goodness. Francis pats him on the back and calls him his oldest comrade. Francis asks if he can bless them and then does so.
Monsignor finishes reading the journal. In the morning he tells Francis that he read it all night. Francis admits he was ineffectual. The Monsignor says he will tell Angus only what will help him. Francis tells a boy to get the fishing rods, and they walk off.
This spiritual drama shows how a sincere man who wants to help people struggles to survive and serve those in China. One bishop is humble and wise, but another is pompous and vain. A doctor who is an atheist and likes to drink is a good man, and a proud nun learns from the humble priest.