An Octave Higher is set in a world called Overture in which the industrial revolution introduced magical science and engineering. With this came a bigger divide between the classes: the bourgeoisie and the proletariat. A struggle appeared among those left at the bottom and the plot is set with a revolution brewing in the background.
On either side of the class divide are Franz Byron, a magical science student, and a factory worked called Elise Shelley. Franz happens across Elise as she tries to cast a healing spell on a broken piano. As he’s researching the effect of healing spells on inanimate objects he decides to take her on as an assistant.
What ensues is a novel-length story with multiple endings as Franz and Elise, as Playism puts it, “each try to find their own meaning, being led astray and brought together multiple times.”