The text opens in the rural village of Dalarna, Sweden, in the late 1800s. Ingmar Ingmarsson, a farmer from a long line of respected community leaders, surveys his bountiful farmlands. Though surrounded by beauty and prosperity, he is forlorn because his wife, Brita, will be released from prison after murdering their newborn child. As Ingmar considers how best to integrate Brita into his life, he contemplates his role in her demise. Though the Ingmarssons are said to "walk in the ways of God" and dispense advice to the community, Ingmar lived with Brita without marrying her and neglected her emotional needs. Thus, Ingmar assumes responsibility and brings Brita home when she leaves prison. During her punishment, Brita deepened her Christian faith and developed loving affection toward Ingmar, though she attempts to hide her feelings. Ingmar's mother and the church congregants shun Brita, but Ingmar, forsaking all sense of decorum, sits with Brita at church in a show of solidarity. After a difficult discussion and mutual forgiveness, the couple is greeted with respect and acceptance. Ingmar's show of support for Brita was "a better sermon" than any the community had ever witnessed, earning Ingmar the epithet "Big Ingmar."
Years later, the Dal River floods, destroying much of the town. Though now sixty-five, Big Ingmar wades into the rapids to save a group of children. In the process, he is struck by a massive log and dies soon after. Ingmar's death incites several changes within the community. Notably, Ingmar's son-in-law, Elof Ersson, becomes addicted to alcohol and gambling and grows verbally abusive and hostile after sustaining a severe injury. Karin, Ingmar's oldest child, and Elof's wife, sends her siblings away to protect them from the toxic home environment. Her sisters she marries off, and her preteen brother, Ingmar, she sends to live with Storm, the schoolmaster. Elof stole Ingmar's inheritance money, and the boy needs an education to succeed financially.
Karin's ex-fiance, Tims Halvor, receives a watch from Ingmar, which Big Ingmar bequeathed to him just before his death as a token of forgiveness. This powerful gesture encourages Halvor to care for Elof Ersson, as Elof was injured at Halvor's store. Soon after, Elof dies. Karin and Halvor rekindle their romance and marry soon after.
Storm, the schoolmaster, builds a mission house, which he believes will encourage the community to engage with religion, thus staving off "heretical" sects of Christianity popping up as the region industrializes. Though his mission is initially a success, villagers feel empowered to preach and oust Storm. Dejected, Storm allows his daughter, Gertrude, and Ingmar, now a teenager, to engage in frivolous activities like attending dances.
One night, Ingmar and Gertrude attend a dance at the home of Big Ingmar's close friend, Strong Ingmar. During the dance, Strong Ingmar suggests that Ingmar build a sawmill on his property to make enough money to buy back Ingmar Farm. Ingmar, who has romantic feelings for Gertrude, believes this business venture will put him in a suitable position to marry. Suddenly, an avalanche tears through the village, which the community interprets as an omen from God; in response to their fear, many develop fundamentalist religious beliefs.
Strong Ingmar's daughter, Ana Lisa, returns from America with her husband, John Hellgum. Though an untalented preacher, Hellgum enraptures the community with his mysterious persona and claims of miraculous healings. Hellgum divides the community, as his followers refuse to associate with "unbelievers" and refrain from attending school or church. Karin becomes one of Hellgum's followers after she recovers from temporary paralysis on the same day she speaks to him.
Ingmar fears that Hellgum will take control of the Ingmar Farm and separate Ingmar from his source of income, as Hellgum attempts to house his commune of believers in Karin's home. When Ingmar goes to confront Hellgum, he sees a group of men attempting to kill the preacher, as they attribute their brother's death to Hellgum's teachings. Though he hates Hellgum, Ingmar steps in and saves his life, becoming severely injured in the process. He only allows Karin to bind his wounds on the condition that Hellgum leave Dalarna and never return. Gertrude visits Ingmar, and the two confess their feelings for one another, vowing to marry as soon as they are financially stable.
The text then conveys a scene from a few years prior, when two ships collide crossing the Atlantic. The passengers, attempting to save their own lives, resort to cruelty and violence. One woman, Mrs. Gordon, loses her children in the wreckage but survives. As she lies in the water, she experiences a spiritual awakening and hears a voice compel her to seek "unity." Upon returning home, she deepens her faith and founds a Christian commune in Jerusalem.
The text then transitions to five years after Hellgum's arrival in Dalarna. Though he is still exiled in America, he preaches to his devout followers, including Karin and Halvor, by sending letters that the devoted gather together and read. In his newest letter, Hellgum insists that God will soon destroy Dalarna, and the faithful should join Mrs. Gordon in Jerusalem, where they will work to end poverty and violence in the region. Though the followers are afraid to leave their homeland, they feel "the Voice of God," convincing them to make the pilgrimage.
To fund their travels, the Hellgumists auction their farms and homes, mainly to large logging companies notorious for damaging the environment and communities through their business practices. On the day Karin auctions Ingmar Farm, many villagers attend to support Ingmar, who does not have enough money to buy back his family's estate. However, Judge Sven Persson purchases the farm and gives it to Ingmar on the condition that Ingmar marry Persson's daughter. Ingmar agrees, forsaking his happiness and his promise to Gertrude to maintain his legacy.
Gertrude suffers intense anxiety after Ingmar's betrayal and is plagued by nightmares where she enacts revenge. While trying to herd her family's cows, Gertrude crosses a stream known for giving people visions and sees the image of a man she believes is Jesus Christ. She converts to Hellgum's religion and secretly joins the pilgrims.
On the day of Ingmar's wedding, Gertrude privately explains her conversion and plans to leave Dalarna. Still in love with Gertrude, Ingmar respects her decision until she gives him his inheritance money, which she found in a pillow purchased at the auction. Ingmar is grief-stricken because if Gertrude had given him the money even a day sooner, he could have bought the farm and married her.
The pilgrims leave for Jerusalem, and the community gathers to say their tearful goodbyes despite their theological disagreements. The Hellgumists view their homeland with new eyes, emotional over the idea that they will never return. When they reach the train station, the children attempt to go back to the village. The novel ends without definitively stating whether the pilgrims boarded the train for Jerusalem or returned home.
