The novel revolves around Martin, a boy with keen interest in science and medicine. He is born and raised in a small town, Elk Mills, and goes on to become a medical student at college, where he meets Max Gottlieb, his mentor. At college, he starts a relationship with a fellow student, Madeline Fox. However, her snobbish attitude and behavior of looking down at those she thinks are beneath her, results in their break up. Martin goes on to fall in love with Leora Tozer, a nurse, whose kind-hearted soul is the complete opposite of Madeline’s.
Martin then begins a conflict within himself between the commercialism of physicians and his true love for scientific research. However, as he needs the money he and Leora move to Winnemac after he graduates, where he becomes the local doctor. However, he is met with dislike, as the townspeople continue to gossip about him, and he also loses a patient of his. Leora also miscarries. This causes him to feel like he has failed and thus they move away to Nautilus.
In Nautilus, he is also unhappy working as a physician and moves on to work at Rouncefield Clinic in Chicago, where his unhappiness follows him. He is saddened by the lack of true care and the greed for money that he witnesses. However, he bumps into his mentor, Max, who offers him a job on the research team at McGurk Research Institute in New York. Initially he is happy about pursuing his dream in research but soon becomes frustrated by the constant pressure to complete his research and show results. He is also under pressure to sell his work, which he is reluctant to do so.
He manages to make a breakthrough in his research, and identifies a treatment for pneumonia and plague. He and Leora then travel to an infected region on the island of St. Hubert to test his treatment. However, Leora dies from the plague and this leads to a halt in his research. His treatment does seem to work on the residents though, but Martin, in mourning, decides to forego his research.
He later meets Joyce Lanyon, whom he marries and has a child with. However, her affluent status and lifestyle bears a constant weight on him, until he leaves the family to travel to the woods with his peer, Terry Wickett, where they continue with their research, without the pressures of businesses.
