Born into poverty and sold into slavery, Vincent de Paul (Pierre Fresnay) survives to become a respected clergyman and a confidante of the nobility. But when the Black Plague descends upon France, Vincent leaves his comfortable post to become a simple parish priest. Single-minded in his devotion to the wretched poor, he rallies the landed class to create charitable organizations, and in the process revolutionizes treatment of the needy the world over.