The Immortal Hour is an opera by English composer Rutland Boughton. Boughton adapted his own libretto from the play of the same name by Fiona MacLeod, a pseudonym of writer William Sharp. The Immortal Hour is a fairy tale or fairy opera, with a mood and theme similar to Dvořák's Rusalka and Mozart's The Magic Flute. Magic and nature spirits play important roles in the storyline. The fairy people are not mischievous, childlike sprites, but are proud and powerful: immortal demigods who are feared by mortals and who can (and do) interfere with the lives of men and women. Alternatively, the progression of Etain into the mortal realm and her pursuit and redemption by Midir have similarities with the legend of Orpheus and Eurydice.