The Spectre Knight is a one-act "fanciful operetta" with a libretto by James Albery and music by Alfred Cellier.
The fashion in the late Victorian era was to present long evenings in the theatre, and so producer Richard D'Oyly Carte preceded his Savoy operas with curtain raisers such as The Spectre Knight.
[2] W. J. MacQueen-Pope commented, concerning such curtain raisers: The Spectre Knight is a particularly long curtain-raiser, with sixteen songs, and running over an hour.
The eccentric Grand Duke, with his daughter Viola and the remains of his court, has been banished and live in a lonely glen where they try to keep up the semblance of their former grandeur.
Otho falls in love with his cousin at first sight, and having learned from her of the legend of the spectre knight who is supposed to haunt the glen, he appears in the disguise of the ghost.