James Donald is "Dr. Marriner", a trailblazing surgeon in 1950s England, who is working on a method of treating infections that resist penicillin. He is optimistic that he can develop something in time to save the life of a young boy who is fighting septicaemia. Meantime, aspiring surgeon "Sophie" (Googie Withers) is facing a dilemma of her own. She is in love with the doctor, but has the opportunity to relocate to a London hospital where her career can blossom more fully. Things come to an head when "Marriner" becomes accidentally infected, too - and she has to make a tough decision that…