In the early 1890s, at the Sorbonne in Paris, Marie Sklodowska, a poor Polish student, faints from hunger during one of Professor Perot's physics lecture. Concerned for Marie's health, Perot invites the gifted scholar to lunch and, after questioning her about her future plans, offers her a research job. Perot suggests that Marie conduct her research at the laboratory of chemistry and physics instructor Pierre Curie and arranges for her to meet him at a dinner party that night. Despite the Perots' attempts to make them comfortable, the absentminded Pierre acts shy around the equally reserved Marie. Before Marie arrives at the lab the next day, Pierre, who believes that women and science are "incompatible," instructs his young assistant, David LeGros, to set up her research equipment in a far corner. David is startled by Marie's attractiveness and awkwardedly shows her to her work station. Weeks later, after work, Pierre shares his umbrella with Marie during a rainstorm and chats with her for the first time. Pierre is greatly impressed by Marie's insightful scientific observations, and soon after, presents her with an inscribed copy of his new book. At that moment, Dr. Becquerel, another scientist in the building, rushes into the lab, anxious to share his latest discovery. Becquerel shows Pierre and Marie a light-sensitive plate with a photographic impression of a key on it. The impression was made inadvertently inside a drawer when the plate came into contact with some pitchblende ore. Marie is fascinated by the phenemenon and wonders aloud how light could be "locked up inside" the rock. Marie then informs Pierre that once she has graduated, she will be returning to Warsaw to be with her father. Although Pierre admonishes her not to give up her research, Marie is adamant about leaving. After Marie is honored at graduation as the top-ranked physics student, Pierre, anxious to delay her departure, invites her to spend the weekend at his parents' country home. There, Marie is welcomed by Pierre's physician father Eugene and his kind, perceptive mother. On the last day of her visit, Mme. Curie suggests that Marie prolong her visit, but once again, Marie insists that she has to return to Poland. Desperate, Pierre bursts into Marie's room that night and proposes they marry and pursue their "common scientific dream." Marie happily accepts and, during their honeymoon, reveals to Pierre that her dream is to uncover the mystery of the pitchblende phenomenon. Encouraged by Pierre, Marie undertakes her investigation of radioactivity, but after weeks of seemingly inaccurate test results, becomes discouraged. When Pierre suggests one evening that her equipment may be faulty, the couple races back to the lab to revamp the machine. The test results do not change, however, and Marie concludes that an unknown light-producing element must be present in the ore. Marie and Pierre eventually identify two elements, which they name radium and polonium, as the source of the radiation. Armed with this new information, Marie and Pierre apply for funding for a new laboratory, but the skeptical university board offers them only a rundown shed. Despite the serious discomforts of the large shed, the Curies begin the tedious process of isolating radium from the ore. A year later, after they have reduced the ore to two bonded elements, barium and radium, Marie consults with a doctor about some odd burns on her hands. Fearing that the burns may eventually become cancerous, the doctor advises Marie to stop the experiment. Marie insists on continuing, however, and comments to Pierre that if radioactive material is capable of burning healthy tissue, it might someday be used to destroy cancerous tissue. Marie then begins wearing gloves in the lab, and the burns disappear. Over the next two years, the Curies undertake to remove the barium from the sample, using a slow crystallization process. On New Year's Eve, the last crystallization is finally complete, and the scientists stare eagerly into the small lab dish, in which they expect to see a chunk of radium. To their great dismay, however, only a stain remains. Marie is crushed by their seeming failure, but later, in bed, she wonders whether the stain is, in fact, the radium. Marie and Pierre then rush back to the lab and are thrilled to see light emanating from the dish, indicating the presence of radium. Later, after they are awarded a Nobel Prize for their discovery, the Curies and their two children, Irene and Eve, enjoy a much-needed country vacation. As Pierre and Marie contemplate their future, which is to include a new, fully equipped lab, Pierre confesses that he has had premonitions about his death and tells Marie that, in the event of either of their deaths, the other must continue their work. On the day of the new lab's presentation, as Marie is being fitted for an elegant gown, Pierre goes out to buy her some special earrings. After leaving the jeweler's, Pierre walks distractedly into the street and is struck and killed by a passing truck. Paralyzed with grief, Marie withdraws from life and listens stone-faced as a concerned Professor Perot counsels her to go on with her work. Later, however, while going through Pierre's last effects, Marie finds the earrings and sobs, finally able to begin healing. Many years later, in honor of the twenty-fifth anniversary of the discovery of radium, Marie, who continued her research, lectures at the Sorbonne. Calling science "the clear light of truth," she advises her audience to "take the torch of knowledge and build the palace of the future."