In which Martin Arrowsmith, earnest and somewhat naïve, undertakes the role of county health officer, facing the rural populace’s stubborn resistance and scorn as he confronts outbreaks of typhoid and small-pox with scientific rigour that unsettles their comfortable complacency. Eventually compelled to leave behind the parochial world of Wheatsylvania, he embarks with Leora toward the bustling city of Nautilus, seeking a larger stage for his idealistic medical ambitions amid the promise of progress and recognition.