The beautiful Jenůfa waits, fearing that her beloved Števa has been taken off to join the army. She is expecting his child, and his departure would jeopardise the forthcoming marriage. Števa’s stepbrother Laca also carries a flame for Jenůfa and asks her about Števa. The delighted Števa arrives with his friends and musicians at the mill – he has not been taken away and, together with the other recruits, celebrates their good fortune with drink. Jenůfa’s strict guardian Kostelnička sees the riotous company with Števa and announces in front of them all that she would only give her consent to a marriage between Jenůfa and Števa after a probation year, during which Števa would not be allowed to drink. Laca convinces Jenůfa that Števa loves her only because of her beauty, and during the argument he cuts her face with a knife.
In fear of disgrace, Kostelnička hides Jenůfa in her home and claims to everybody that she has left for Vienna. In the meantime, Jenůfa has given birth to a son. Whilst Jenůfa is sleeping, Kostelnička humbles herself before Števa and begs him to marry Jenůfa. For Števa, however, Jenůfa’s scarred face has rendered her ugly, and besides, he is already engaged to the Mayor’s daughter. Laca arrives and asks Kostelnička to hand over Jenůfa to him. When Kostelnička gives away the secret to him that Jenůfa has given birth to Števa’s child, he is shocked. Seeing his doubts, Kostelnička in desperation lies that the child died immediately after the birth. As soon as Laca leaves, Kostelnička drowns the child in an icy river and convinces Jenůfa that she has slept for several days in a fever and the little boy has died in the meantime. The devastated Jenůfa agrees to a marriage with Laca.
During the preparations for the wedding between Jenůfa and Laca the news breaks out that a dead child has been found in the river. Jenůfa recognises her little boy’s bonnet and the suspicion of murder falls upon her. Kostelnička admits her crime in front of the assembled guests. Before the Mayor leads her off to court, Jenůfa forgives her, for she understands that she did it out of love for her. Jenůfa does not believe that Laca would still want her and sends him away. However, Laca wants to stay by her side and promises that he will stay with her even when times are bad. Jenůfa realises that she has found her true love “and God is pleased with it”.