Featuring a concertante organ part, A Choral Fantasia also involves a soprano soloist, chorus, string orchestra, brass and percussion.
The finished work is scored for the unusual forces of organ, brass, percussion and strings with chorus and solo soprano.
The Fantasia opens with a colossal fortissimo prelude for organ in the phrygian mode leading to a chord – causing one reviewer in The Observer to comment, in a spirit of an all too prevalent parochialism, that "when Holst begins his new Choral Fantasia on a six four of G and a C♯ below that, with an air of take it or leave it, one is inclined to leave it" – which introduces the soprano ("Man born of desire, cometh out of the night") over almost inaudible organ line.
A chromatic fugato section bearing the otherworldly bleakness of Egdon Heath and Saturn follows before trumpets, trombones and timpani rise menacingly in 54 introducing an important, typically Holstian, ostinato figure.
The chorus enters, hymnlike, in 74 with the words "Rejoice, ye dead where ere your spirits dwell" to diatonic brass accompaniment.