This plot summary of The Mysterious Mother attempts to preserve the flow of information as it is revealed to the viewer. The gothic tragedy opens as Edmund, Count of Narbonne, returns to his ancestral home from the crusades with his friend and fellow soldier Florian. Edmund was banished by his mother, presumably because he arranged to sleep with a lady’s maid, Beatrice, the night after his father’s death. Edmund has had no contact with his mother for sixteen years, though she has sent him money from the estate she has inherited (a breach of patrilineal protocol motivated by her late husband in his love for her). Edmund assumes that she is being manipulated by the priest of the adjacent abbey, Father Benedict, and his protégé Father Martin, but on his return, he finds her defiant, refusing to confess and yet clearly tormented. She is convinced she has hallucinated her husband’s ghost when she first sees him. Edmund, stunned by his mother’s majestic demeanor in the midst of her distress, nonetheless hopes for a reconciliation through his newfound love for her young ward, Adeliza. The Countess misunderstands the proposed union, thinking that Florian loves Adeliza. Father Benedict begins to connect the dots of her guilt, seizes the moment for his vengeful triumph over the Countess, and hastily marries the unwitting Adeliza to Edmund who, when they come to seek the Countess’s blessing, instead drive her to the horrified confession that Benedict has been trying to extract for years: that her sexual longing for her husband, who unexpectedly died before he could return to her bed, drove her to disguise herself as Beatrice, the maid her son Edmund was to sleep with that night, and put herself in his bed. Edmund is unaware of the bedtrick, but the Countess knowingly has sex with her son. They conceive Adeliza and launch a lifetime of alienation and guilt. When the secret finally explodes in the revelation of a now-double incest plot, the Countess commits suicide with a dagger. Edmund, shattered, vows to return to the wars while Adeliza retreats to a convent.