The prelude opens with a "serene" theme in D flat. It then changes to a "lugubrious interlude" in C sharp minor, "with the dominant pedal never ceasing, a basso ostinato". The repeating A flat, which has been heard throughout the first section, here becomes more insistent. Following this, the prelude ends with a repetition of the original theme. Niecks says, "This C sharp minor portion...affects one like an oppressive dream; the re-entrance of the opening D flat major, which dispels the dreadful nightmare, comes upon one with the smiling freshness of dear, familiar nature – only after these horrors of the imagination can its serene beauty be fully appreciated.