Fall. Jenůfa is worried; if her fiancé Števa is drafted into the army, they can’t wed before people realize that she’s pregnant with his child, a fact that she has kept secret from everyone, including her widowed stepmother, Kostelnička (The Sacristan — a title earned from her service to the church and her unyielding beliefs).  Laca, Števa’s younger half-brother, also loves Jenůfa and resents Števa’s good looks, his inherited wealth (due to an “eldest-boy-gets-the-most” tradition), and his success in winning Jenůfa’s hand. When the foreman tells Jenůfa that Števa wasn’t drafted, she is overjoyed by the news, while Laca is angry. A drunken Števa arrives with new inductees and some musicians. They celebrate, singing and dancing, until they’re interrupted by Kostelnička, who proclaims that Jenůfa and Števa can’t wed until he has remained sober for an entire year. Števa leaves after reassuring Jenůfa that he will be faithful to her despite his roving eye. Laca, nearly mad with passion for Jenůfa, tells her that Števa is interested only in her beauty. They quarrel and Laca cuts Jenůfa’s face with his knife.

Late Winter. Kostelnička has informed the townspeople that Jenůfa is away on a long stay in Vienna; actually she has given birth to a boy, and mother and son are now in hiding at Kostelnička’s home. Kostelnička gives Jenůfa a sleeping remedy and then summons Števa. He agrees to support his son financially but refuses to marry Jenůfa because of her scarred face, and he leaves. Kostelnička tells Laca that the baby has just died. Alone again, Kostelnička imagines her disgrace, then comes to an abrupt decision: “I’ll send the boy back to the Lord!” She takes the child and runs out into the cold. Jenůfa awakens and begins praying for her missing baby. Kostelnička returns and tells Jenůfa that while she has been asleep for two days, the baby has died and Števa has refused to marry her. Laca returns and asks Jenůfa to marry him, and she agrees.

Spring. The family and guests arrive for the wedding. Just as the ceremony begins, a cry goes up — a dead baby has been found, frozen under the ice. Jenůfa recognizes the baby as her son. When the villagers accuse Jenůfa of murder, Laca protects her. Suddenly, Kostelnička admits her guilt. When Kostelnička asks Jenůfa forgiveness, Jenůfa grants it and Kostelnička is led off to stand trial. Jenůfa and Laca are left alone to decide upon their future.