Paul and Adèle, two disabused extras in the opera Tristan und Isolde, make the most of a break and wander off in search of the underground lake at the Palais Garnier. It is a labyrinthine journey into the deepest recesses of the Opera, accompanied by a tortuous discussion on love, which will have the effect of a magic philtre upon them, just like the two Wagnerian protagonists. As if it were impossible to escape from legends and myths. "There is, no doubt that somewhere within reach, lies a hidden world of age-old treasures buried beneath our feet. I like to believe that we are constantly transfixed by myths, dreams and legends. That the past and the present are but one. That it is enough to pay attention to the signs and to strip away the veil of reality to discover the other dimension. In the very centre of Paris, between a Uniqlo, an Apple Store, and the various purveyors of vacuum cleaners along the Grands Boulevards, there it stands, the Palais Garnier, crowned for our visual pleasure with a statue of Apollo as if to remind us that beauty still gazes down upon us. Every evening, the curtain rises to summon the sublime and the ghosts of times past. A friend once told me of the existence of a hidden lake under the Opera. I wanted to believe it and go in search of it in the company of Paul and Adèle, two imaginary extras in the opera Tristan und Isolde.