As so often in opera, the fidelity of women is put to the test in this tale, too: in a medieval, fantastical age of chivalry, the noble Count Adolar is engaged to the sensitive Euryanthe, who has already rejected Count Lysiart. Out of jealousy, Lysiart now intends to destroy the couple’s happiness. He provokes Adolar, who never tires of extolling the purity and fidelity of his betrothed, to accept a risky wager on her resolve. However, Lysiart fails in his attempt to seduce Euryanthe. So he tries a trick and forms an alliance with the equally jealous Eglantine who is suffering on account of her unrequited love of Adolar. Eglantine succeeds in drawing an embarrassing family secret from Euryanthe that she had been made to swear never to reveal: Adolar’s lovesick sister Emma committed suicide with poison from a ring and now her ghost restlessly roams the grounds. Her soul will find no peace until the ring from which she took the drink of death is moistened by the tears of innocence and utmost sorrow. This ring, taken from Emma’s tomb, becomes the corpus delicti and causes Adolar to believe that Euryanthe had entrusted it to Lysiart, along with his secret, in a night of passion. In the presence of the unsuspecting Euryanthe, the wager is ended before the entire court: Adolar loses his lands, his fortune and his bride. He publicly disowns Euryanthe who is speechless with horror and bewilderment. Her inability to defend herself is taken as proof of her guilt and Adolar banishes her to the wilderness. At the last moment, the king discovers her there and saves her from starvation. Euryanthe regains the power of speech and now reveals the full extent of the conspiracy which she saw through after much thought in the forest. Just as Eglantine and Lysiart are about to marry, the wicked couple is visited upon by fate’s vengeance: under the weight of her guilt, Eglantine loses her mind and reveals all. Adolar is now gripped by deep remorse. The king then summons Euryanthe, whom Adolar believes dead, to appear before him. The kind-hearted lover forgives Adolar the idiotic wager and his false accusations. The lovers are reunited, and Emma’s soul also finds peace — the tears of the innocent Euryanthe have moistened her ring.