The first series of the TV drama based on the lives of William Masters and Virginia Johnson, who conducted pioneering research into the nature of human sexual attraction.

Dr William Masters (Michael Sheen) is a leading US obstetrician determined to launch a study of human sexual behaviour. When he makes the acquaintance of Virginia Johnson (Lizzy Caplan), Masters finds an assistant who possesses the qualities to help him move forward with his plan.

Though in many ways Masters and Johnson are polar opposites, as their project progresses a growing sense of attraction develops between the two and the line begins to blur between their personal and professional interests.