Part social-issue film, part feminist melodrama, La Mort du soleil was made with support from the American Committee against TB. A committed young doctor, Marthe Voisin, works long hours assisting Lucien Faivre in his search for a cure for tuberculosis. Jealous of her devotion to her work and to her colleague, Marthe's husband leaves her, taking their son with him. Years later, when her son becomes ill, she decides to return to her family, and Faivre resorts to desperate measures to get her back. In La Mort du soleil Dulac begins to explore the subjective states-anxiety, grief-of her characters, and it is here that she speaks of first using “‘technical acrobatics,' considering that...fade-outs, dissolves, superimpositions, masks, irises, etc., had a suggestive value...equivalent to musical signs,” though some of these were cut because they were considered incomprehensible. The film also includes unusual allegorical depictions of disease and health, including prehistoric beings crawling through desert landscapes, raising their fists at the sun.