Based on the biography by their daughter Eve Curie, two great physicists form a working partnership and marriage that enables them to discover the new element radium.
Marie Sklodowska (Greer Garson) studies at the Sorbonne and faints from hunger. Professor Perot (Albert Bassermann) helps her and introduces her to Pierre Curie (Walter Pidgeon). Pierre tells his assistant David (Robert Walker) that females are dangerous to science, but he lets Marie work in his physics lab on her project. Pierre and Marie discuss science, and he gives her a copy of his new book. Dr. Becquerel (Reginald Owen) shows Pierre and Marie a rock that emits rays of light. David tells Pierre that Marie is planning to return to Poland after her exams. Pierre urges her to stay and do science. Marie graduates first in physics, and Pierre invites her to visit his mother (May Whitty) and his father Eugene Curie (Henry Travers). During the night Pierre wakes up Marie and asks her to marry as a collaboration. Marie agrees to stay in Paris. They marry and leave on bicycles for a honeymoon. Marie decides to work on the energy in the rocks but gets frustrated. Pierre's parents come for dinner, and Pierre helps Marie with a problem. Uranium and thorium only account for half the energy in the pitchblende. Marie tests the .001% of unknown material remaining, and it accounts for half the energy. Marie and Pierre deduce a new and active element that Marie names radium.
A board asks for more proof and can only let them use an old shed. Pierre and Marie work on isolating the radium from tons of pitchblende. After years of hard work they still have to separate barium from the radium, but 458 experiments fail. A doctor examines unusual burns on Marie's hands and warns of cancer. Pierre is worried and advises stopping, but Marie suggests that the energy could destroy unhealthy tissue. Gradually they remove some barium a little at a time. Perot and Lord Kelvin (C. Aubrey Smith) come to see the last crystallization, but only a stain remains. Pierre's father complains about the child Irene, and Pierre tells her a story of a princess who is searching for a treasure in a stone. Pierre and Marie celebrate the new year. That night Marie realizes the stain may be the radium and sees it glowing in the dark. They become famous, and Eugene Curie turns away journalists. On vacation Marie tells a cub reporter (Van Johnson) of their new lab. Marie has a new dress for the ceremony, and Pierre buys earrings for her; but he is run over by a horse-drawn carriage and dies. Perot urges Marie to do what Pierre would want and continue to work. She finds the earrings and cries. Twenty-five years later Marie speaks in a large auditorium about her dreams of scientific progress.
This true story of dedicated scientific researchers portrays
their eccentric but humanitarian life-style. Marie did live on
bread and butter at the Sorbonne, but their sacrifices eventually
resulted in important discoveries.