The lives of sex researchers William Masters and Virginia Johnson are depicted in this critically acclaimed drama. Season 1 begins with Masters (Michael Sheen), a successful gynecologist at Washington University in St Louis, conducting a secret study of human sexuality. Soon, he meets Virginia Johnson (Lizzy Caplan), a former nightclub singer who is now part of the hospital secretarial staff. He enlists her help with his study, and she quickly proves to be an asset to Masters's work. Together, they delve deeper than anyone before them into the science of sex and later become participants in their own research, which takes an unforeseen toll on Masters's married life.