The scene is an artist's room cluttered with a variety of musical instruments, especially percussion, which seems to include saucepans. When the curtain rises Séraphin, a servant, explains that his master is a composer, but unfortunately crazy. When Fignolet arrives, Séraphin is called upon to assist in a performance of his new symphony. It is a programmatic work, entitled Gigomar Fallen to the Invaders. Séraphin asks whether this refers to the elder or the younger Gigomar, to which Fignolet responds by pointing out that Gigomar is a place, not a person, and the action is set in the year 14, 894. Séraphin's contributions on the bass drum are appreciated, but the bits of leftover food Fignolet finds in the piano make him cross — has he not asked Séraphin to stop cooking over the piano? They work their way enthusiastically to the end of the piece, however, which ends with a victory hymn, after which they shake hands as they bow to the audience.