Richard Wagner is working on his new opera "Tristan and Isolde". Mathilde Wesendonck and her husband, the silk-merchant Otto Wesendonck venerate Wagner. Mathilde is turning from a loving mother into a muse of the new music.

It's the first time Adrien is entering a homosexual sauna. In the space of one night, he discovers this microcosm where the comic aspect of the individual tragedies encounters the passing of time and where hope mingles with melancholy.