In 1860 Finland, the young Count Mauritz Armborg and Katariina, the daughter of a farmhand on the Count's estate, find themselves drawn to one another. Yet Mauritz’s grandmother, Yvonne Armborg, stands in their way, opposing the romance and scheming to keep the lovers apart. Meanwhile, Elias Jahnukainen, a fisherman who also loves Katariina, hopes to marry her, but she has so far rejected him. To derail the couple, Countess Yvonne offers to finance Katariina’s dowry if she agrees to marry Elias, and she introduces Mauritz to Ingeborg Liliecrona, though Mauritz does not feel a spark for her.
The two lovers dare to dream of eloping, planning a trip first to Copenhagen and then to Rome. They meet at an inn and share a night of closeness, but at dawn Mauritz leaves Katariina with an old family heirloom necklace. A servant loyal to Yvonne betrays their plans, and Katariina is escorted back to her life, while Mauritz presses on alone. Grief and misfortune deepen the rift: Katariina, despondent, attempts suicide by leaping from a cliff, only to be saved by Elias. She ultimately agrees to marry Elias, while Mauritz reaches Copenhagen, where a severe illness keeps him confined for weeks.
In Copenhagen, Ingeborg travels to meet Mauritz and falsely tells him that Katariina will arrive in Rome with Countess Yvonne. But when they reach Rome, Yvonne arrives alone and breaks the devastating news: Katariina has married Elias, leaving Mauritz distraught and heartbroken. Katariina and Elias relocate to the Katajanokan district, and Katariina gives birth to a son who is named Mauritz. Although the boy’s biological father is Mauritz, Elias promises to raise him as his own.
Seven years pass. Mauritz and Ingeborg are married, yet Mauritz remains unhappy, still in love with Katariina. Finland endures famine and plague, and Katariina writes to gain admission for her son into a good school. Her application fails, in part because Elias’s social status is too low. One day, the young Mauritz disappears. Katariina finds him at the governor’s wife Elisabeth Gerhard, whose own son has died. Elisabeth Gerhard offers to care for the boy. She travels to Rome with Mauritz, where the boy meets Count Mauritz and sees the necklace, realizing he is Katariina’s son and thus the Count’s own kin.
The elder Count’s marriage to Ingeborg collapses, and Countess Yvonne, who has since repented of her scheming, begins to feel affection for the boy. Mauritz and the boy return to Munkkiniemi to a solemn, heartfelt welcome. As Yvonne encounters the returned child and recognizes their kin, Katariina also learns of her son’s return. In a quiet park, Mauritz softly sings the Romance the lovers once shared. Katariina hears the familiar tune, and the two reunite. Mauritz asks Katariina to come home with him, to their home, closing a long chapter of separation with a hopeful, lasting union.
