The mortal princess Semele faces divine retribution and tragic transformation after becoming the lover of the god Jupiter. Semele seeks to elevate her status by demanding immortality from her divine lover, a request that triggers the jealousy of Juno. The narrative follows the conflict between human ambition and the volatile whims of the Olympian gods. Structured as a three-act libretto, the text utilizes formal verse to delineate the psychological descent of the protagonist. The plot operates within the constraints of classical mythology, emphasizing the inevitable clash between mortal desire and divine power.

Discussion often centers on the unique hybrid nature of the work, which occupies a space between traditional opera and English oratorio. Readers and critics frequently highlight the sharp, witty characterization of Semele, noting how the text avoids the typical moralizing tone of the period. The pacing is noted for its rapid escalation toward the final catastrophe, reflecting the intensity of the protagonist's fatal ambition. Scholars often examine how the libretto balances the lighthearted satire of the opening scenes with the somber, tragic conclusion. The work remains a subject of analysis for its sophisticated use of language and its departure from the standard operatic conventions of the eighteenth century.