The poem’s title alludes to the popular Greek myth of Persephone, daughter of the harvest goddess, and Persephone’s lover Hades, the god of the underworld. As a deity who spends half of the year below ground in the land of the dead and the other half in the brightly lit land of the living, Persephone is associated with the concept of duality. Therefore, the “two sisters” are the two competing identities of Persephone, which represent the paths and choices of women.

The poem contains short lines and clear, simple language. Plath uses enjambment (the continuation of an idea from one line to the next without using the absolute of end punctation, or easing the flow using commas) and caesura (a punctuated break in the middle of the line) to create a “hall of mirrors” effect in which each moment takes on multiple meanings. The opening lines, “Two girls there are: within the house / One sits; the other, without” (Lines 1-2), mean something different depending on where the punctuation guides the reader’s eye. The poem will straddle two worlds, which is shown in splitting the first line down the middle and directly referencing this duality in the following lines: “Daylong a duet of shade and light / Plays between these” (Lines 3-4).