Literate Provincetown bohemians Toby and Lou Maytree meet and marry, have a son, and begin to grow old before Toby decides to leave for Maine to build a new life with a family friend. Toby and Lou remain estranged as the book follows both characters through life's progress: Lou raises their son and Toby and Deary develop a successful business. When Deary falls ill and Toby loses his ability to care for her, the families are reunited.