Allegro dramatizes, with the help of a chorus that both narrates and comments on the action, the first 35 years of the life of Joseph Taylor, Jr., starting on the day of his birth in an unnamed small town where his father is the town doctor. We follow him through his time in college and medical school, to his move to Chicago during the Depression, where he has been offered a partnership in a large practice catering primarily to the wealthy and connected to a major hospital. This decision is made primarily at the urging of his strong-willed wife, Jennie, whose family was well off before the Depression and who is tired of being married to a poor doctor.
In Chicago, he finds himself functioning more as a administrator than as a doctor who helps people truly in need. A combination of personal and moral crises and issues leads him to leave his wife and return to his hometown.