Act IV opens as a voice fills the forest near Prometheus's cave as Ione and Panthea sleep. The voice describes the dawn before a group of dark forms and shadows, who claim to be the dead Hours, begin to sing of the King of the Hours' death. Ione awakes and asks Panthea who they were, and Panthea explains. The voice breaks in to ask "where are ye" before the Hours describe their history. Panthea describes spirits of the human mind approaching, and these spirits soon join in with the others singing and rejoice in love. Eventually, they decide to break their song and go across the world to proclaim love. Ione and Panthea notice a new music, which Panthea describes as "the deep music of the rolling world/ Kindling within the strings of the waved air,/ Æolian modulations." Panthea then describes how the two melodies are parted, and Ione interrupts by describing a beautiful chariot with a winged infant whose "two eyes are heavens/ Of liquid darkness, which the Deity/ Within seems pouring, as a storm is poured/ From jagged clouds" and "in its hand/ It sways a quivering moon-beam". Panthea resumes describing a sphere of music and light containing a sleeping child who is the Spirit of the Earth.