An audience of angels gathers to watch a play. Mimes fly around the stage, seemingly as puppets driven by invisible forces, and the plot describes sin, madness, and horror. The crawling Conqueror Worm then appears, writhing as it eats the mimes. The curtain falls, and the distressed angels affirm that the play is a tragedy called "Man" and that the Conqueror Worm is the hero.
In its relatively brief five stanzas, "The Conqueror Worm" seeks to tell the allegorical history of mankind. The work acts as a frame story, where the outside frame is that of a throng of angels watching a play, and the inside frame is that of the play itself. As a narrative poem, "The Conqueror Worm" also contains a typical plot construction. The first stanza serves as the exposition, placing the angels at night in the setting of a theatre, while the second and third stanzas provide the rising action. The climax comes with the entrance and triumph of the Conqueror Worm, and the last stanza returns to the outside frame for the falling action and denouement.
Poe believed strongly in the aesthetic benefits of ensuring a unified mood throughout a poetic work, and he establishes the tone of his poem in the first stanza, as he introduces the image of angels "bedight in veils, and drowned in tears." The angels are associated with goodness and with Heaven, and their sorrow provides an early indication that the play will be a tragedy, although the protagonist has yet to enter the stage. As the play progresses to its completion, we find that humanity is merely a mass of faceless puppets who are victims to the true protagonist, the Conqueror Worm. In this tragedy called "Man," the Worm acts both as a particularly bloody Grim Reaper and as an interpretation of the evil serpent from the Biblical Garden of Eden. Unlike in most tragedies, however, the hero does not die but instead achieves victory, and the angels cannot help but mourn.
In Poe's understanding of humanity in "The Conqueror Worm," people are controlled by unseen and mysterious forces. Consequently, "Madness," "Sin," and "Horror" constitute the majority of the plot, a fact emphasized by the capitalization of these words within the poem. Curiously, for Poe, part of the tragedy of man is that the angels cannot help them but instead merely watch and witness as the Conqueror Worm devours. The last stanza turns the curtain into a metaphorical funeral pall, and the lines juxtapose the "rush of a storm" of the curtain with the "pallid and wan" exteriors of the angels. Death, as signaled by the curtain, has finality and a power that the angels lack.
After Poe authored "The Conqueror Worm," he chose to add it to his Gothic short story "Ligeia." In "Ligeia," the eponymous character writes the poem and shows it to her husband prior to her death. After he recites it for her, she screams at the injustice of the poem's suggestions about existence and quotes the epigraph of the story, which is supposedly written by Joseph Glanvill and which states that man only dies because of his lack of will. The sense of despair in the poem contrasts with Ligeia's resistance, and by the end of the story, Ligeia has seemingly found the will to return from the dead by taking over another woman's body. Nevertheless, Poe leaves open the question of whether her return is merely her husband's hallucination, and the inclusion of the poem complicates the truth of the visions of both the poem and the story.
In terms of structure, the poem adheres to a strict rhyme scheme, where each eight-line stanza takes an ABABCBCB pattern. The rigidity of this construction proves a harsh framework for the internal rhymes and the irregular, albeit melodic, rhythms of the poem. Meanwhile, Poe uses exclamations to break the rhythm into cacophonous explosions of sound. For instance, the phrase "It writhes! - it writhes!" continues the iambic rhythm that predominates in the fourth stanza, but the hyphens and exclamation points indicates pauses which disturb the poem's flow. Finally, the alliteration within phrases such as "lonesome latter years" and "mutter and mumble low" generally serves to emphasize the gloomy mood of the poem while adding to the lyrical effect.