An idealistic young medical student, Martin Arrowsmith, introduces himself assertively to Dr. Max Gottlieb, a noted bacteriologist. Though Gottlieb deems Arrowsmith not yet ready to study with him, he is impressed by the young man's determination and honest self-appraisal, and encourages him to take the standard course of study first. When Arrowsmith graduates, Gottlieb offers him a position as his research assistant, but the young man reluctantly turns him down, having fallen in love with a nurse, Leora. He would be unable to support her on a research assistant's meager salary. He marries, and the couple sets off for Leora's rural home town in South Dakota.