Lambert of FÜrstenberg was a hearty jovial knight, and had married Wiltrud, a daughter of the Florsheim family. He was attached to his gentle wife, who had just presented him with a son and heir. But an evil genius entered the castle in the person of a noble maiden called Luckharde. This maiden who had suddenly been left an orphan, belonged to a family long befriended by the house of FÜrstenberg. She was only eighteen, but possessed a lascivious beauty, very dangerous to men.

The lady of the castle, who had been in delicate health since the birth of her child, gave Luckharde a warm-hearted welcome into the bosom of her family, trusting that the young woman would be of great service to her in the management of her little realm, and would repay her kindness by sisterly love and sympathy. Luckharde however was of a vain and frivolous disposition, and had little love for household affairs, or womanly duties.

As the months passed, Luckharde's ripening and dangerous beauty gained gradually and almost imperceptibly more and more influence over the susceptible heart of the lord of the castle, and soon the day came when he yielded himself entirely to the charms of this beautiful woman. Wiltrud's eyes were by no means blind to the shameful ingratitude of the adulteress, and the godless conduct of her husband. Her weakness however, prevented her from calling down the judgment of heaven on the sinners. Luckharde, led on by her unbridled passion, now formed a devilish design which would enable her to take the place of the lawful wife of Lambert. One night she slipped into the chamber of the lady of the castle, approached the bed of the sleeping woman with a cat-like step, and smothered her with the pillows, the poor invalid offering but a feeble and ineffective resistance.

Wiltrud's death was deeply mourned by the household, who believed that she had died of a broken heart. Lambert too might be grieved, but in the arms of his raven-locked enchantress he soon forgot his deceased wife, and in a few weeks Luckharde was made lady of FÜrstenberg. The little boy whom Wiltrud had borne to her unfaithful husband was hateful to the second wife, who fondled her lord, and flattered him with the hope of the children she would bear him. Then it was arranged that the knight's first-born should be handed over to the care of an old crone who lived in a remote tower of the castle.

One night this old woman awoke suddenly, and was terrified to see a female form dressed in a flowing white robe, bending over the cradle of the little boy, who slept near. The woman seemed to be tending the child, and after blessing him, she vanished. The old woman crossed herself, and in terror muttered many prayers. In the early morning she hurried to her new mistress in great agitation and with white lips told her of her strange visitor. Luckharde at first laughed in her usual frivolous manner at this ridiculous ghost story, but soon she became more serious and alarmed. Then she ordered the old woman to arrange her bed beside the other servants, but still to leave the child in the tower-chamber. A dreadful fear had taken possession of Luckharde's guilty soul. Perhaps people were deceived when they believed Wiltrud to be dead, and it was thus that she returned at night to nurse her child.

Then this daring and sinful woman prepared a bed for herself in the lonely tower beside the child. She also brought with her a formidable dagger, and thus she awaited what the night might bring forth. At midnight the female figure dressed in the flowing white robe appeared once more. It approached the cradle of the child, tended him and blessed him. Then the terror-stricken Luckharde stared motionless at the apparition as it rose and approached her bed. Towering there above her were the pallid features of the dead Wiltrud, and the lifeless entreating eyes looked steadily at this sinful woman who had taken the place of her benefactress. To Luckharde it seemed as if a great precipice was slowly bending over to overwhelm her. With a last mad effort the wretched woman seized the dagger, and struck at the apparition; but she might as well have struck at a misty cloud. Now Luckharde perceived that she was in the presence of the murdered lady of the FÜrstenberg, and harrowed with the thought of her guilt she seemed to hear a voice as if from another world saying, "Do penance for thy sins."

Next morning Lambert waited in vain for his wife to appear. On looking around however he noticed a piece of parchment. On it Luckharde had confessed with deep sorrow, how she had murdered his first wife in order to further her evil designs, and how the spirit of the dead had appeared to her in the night, and warned her of her great guilt. She was going to fly to a cloister to do penance during the remainder of her days, and she recommended her sinful accomplice to do the same. Lambert of FÜrstenberg was deeply grieved on receiving this revelation. He handed over his castle and child to a younger brother, and spent the rest of this life as a solitary hermit.