Out of sight, a factory produces a chromic-sulfuric mix which is used in the industry to dissolve organic matter. Zaïna and her apprentice Romuald keep a watchful eye on the aera.
Laure cleans in a Parisian apartment belonging to the Saudi royal family. When unknown men come into the apartment, Laure is forced to hide in a storeroom with her boss. The two women must remain silent, glued to each other.
