The following act introduces us to Reinhardt's studio in a German residence. A year has gone by since he wooed and won his bride; alas, he is already tired of her. The siren Maria countess of Matran, with whom he was enamoured years ago and whose portrait he has just finished, has again completely bewitched him.
In vain Lorle adorns herself in her bridal attire at the anniversary of their wedding; the infatuated husband has no eye for her loveliness, and roughly pushes her from him. Left alone the poor young wife gives vent to her feelings in an exquisite sigh of longing for her native country. "Hätt' ich verlassen nie dich, meine Haiden." (Would I had never left thee, o my heath.)
A visit from her dear Bärbele somewhat consoles her and delights Walter, the faithful house-friend. Balder, Lorle's old play mate, still recruit, also comes in and gladdens her by a bunch of heath-flowers. But hardly have they enjoyed their meeting, when the prince is announced, who desires to have a look at the countess' portrait. The rustic pair are hastily hidden behind the easel, and Lorle receives his Royal Highness with artless gracefullness, presenting him with the flowers she has just received. Her husband is on thorns, but the prince affably accepts the gift and invites her to a festival, which is to take place in the evening. Then he looks at the picture, expressing some disappointment about its execution, which so vexes the sensitive artist that he roughly pushes the picture from the easel thereby revealing the two innocents behind it. Great is his wrath at his wife's imprudence, while the prince exits with the countess, unable to repress a smile at the unexpected event.
There now ensues a very piquant musical intermezzo, well making up for the missing overture. The rising curtain reveals a brilliant court festival. Reinhardt has chosen the countess for his shepherdess, while Lorle, standing a moment alone and heart-sore, is suddenly chosen by the Prince as queen of the fête. After a charming gavotte the guests disperse in the various rooms. Only the countess stays behind with Reinhardt and so enthralls him, that he forgets honor and wife, and falls at her feet, stammering words of love and passion. Unfortunately Lorle witnesses the scene; she staggers forward, charging her husband with treason. The guests rush to her aid, but this last stroke is too much for the poor young heart, she sinks down in a dead faint.
The closing act takes place a year later. Walter and Bärbele are married, and only Lorle's sad fate mars their happiness. Lorle has returned to her father's home broken-hearted, and this grief for his only child has changed the old man sadly.
Again it is midsummernight, and the father is directing his tottering steps to the old oak, when he is arrested by a solitary wanderer, whom sorrow and remorse have also aged considerably. With disgust and loathing he recognizes his child's faithless husband, who comes to crave pardon from the wife he so deeply wronged. Alas, he only comes, to see her die.
Lorle's feeble steps are also guided by her friends to the old oak, her favorite resting-place. There she finds her last wish granted; it is to see Reinhardt once more, before she dies and to pardon him. The luckless husband rushes to her feet and tries vainly to restrain the fast-ebbing life. With the grateful sigh "he loves me", she sinks dead into his arms, while a sweet and solemn choir in praise of St. John's night concludes the tragedy.