Place:  A Moravian village
Time: the nineteenth century

The plot depends on a tangled set of village relationships. Before the opera begins, the mill-owner Grandmother Buryja's two sons have both married twice, fathered children, and died. Their wives have also died, except for the Kostelnička (widow of the churchwarden), the younger son's second wife and Jenůfa's stepmother. Custom dictates that only Števa, the elder son's child by his first marriage, will inherit the mill, leaving his half-brother Laca and cousin Jenůfa to earn their livings.

Act 1

Jenůfa, Laca, and Grandmother Buryja wait for Števa to return home. Jenůfa, in love with Števa and secretly pregnant with his child, worries that he may have been drafted into the army. Laca, in love with Jenůfa, expresses bitterness against his half-brother's favored position at home. As he complains he plays with a knife and, finding it blunt, gives it to the mill foreman to be sharpened.

The foreman informs the family that Števa has not been drafted, to Jenůfa's relief and Laca's increased frustration. The others leave, and Jenůfa waits to greet Števa. He appears with a group of soldiers, drunk and boasting of his prowess with the girls. He calls for music and drags the miserable Jenůfa into dancing with him.

Then Kostelnička steps into this rowdy scene, silences the musicians and, shocked by Števa's behavior, forbids him to marry Jenůfa until he can stay sober for one full year. The soldiers and the family leave Števa and Jenůfa alone, and she begs him to love her, but he, unaware of her pregnancy, gives her casual answers and leaves.

Laca returns, as bitter as ever. He attempts to goad Jenůfa into criticizing Števa, but she takes her lover's side despite everything. Laca rages that Števa would never even look at her if it weren't for her rosy cheeks, then slashes her across the cheek with his knife.

Act 2

Months later, it is winter. The baby has been born, but Števa has not yet come to visit his child. Jenůfa's face is still disfigured, but she is happy in her love for the baby. While Jenůfa sleeps, the Kostelnička summons Števa and demands that he take responsibility. He answers that while he will provide money in secret, no one must know the baby is his. His love for Jenůfa died when Laca spoiled her beauty, and he is now engaged to marry Karolka, the mayor's pretty daughter.

Števa leaves, and Laca enters. He still doesn't know the truth about the baby, and when the Kostelnička tells him, his first reaction is disgust at the thought of taking Števa's child under his wing. Fearful that Jenůfa will be left with no one to marry, Kostelnička hastily lies that the baby is dead. Laca leaves, and the Kostelnička is faced with the necessity of making the lie true. She wraps the baby in a shawl and leaves the house.

Jenůfa wakes up and says a prayer for her child's future, but the Kostelnička, returning, tells her that the baby died while she slept. Laca appears and comforts Jenůfa gently, asking that they spend the rest of their lives together. Seeing the tenderness of the couple, the Kostelnička tries to convince herself that she has acted for the best.

Act 3

It is now spring, and Laca and Jenůfa's wedding day. All seems right again, except that the Kostelnička is a nervous wreck. Števa and Karolka visit, and a chorus of village girls sings a wedding song. Just then, screams are heard. The body of the baby has been discovered in the mill-stream under the melting ice. Jenůfa immediately says that the baby is hers, and in her grief appears guilty of the murder. The village is ready to exact immediate justice against Jenůfa, but the Kostelnička calms them and says that the crime is hers. Hearing the whole story, Jenůfa forgives her stepmother. The crowd takes the Kostelnička off to jail. Jenůfa and Laca are left alone. Jenůfa asks Laca to leave her, as she cannot expect him to marry her now. He replies that he will not leave her, and that he wishes to spend the rest of his life with her.