The novel is set in the fictional Massachusetts town of Durham shortly after World War I. The Pentland family is rich and part of the upper class, but their world is rapidly changing. The old Congregational church the Pentlands long favored has disbanded as more and more WASPs have left Durham, replaced by immigrant Roman Catholics with very different religious customs. The Pentlands once ruled upper-class society in Durham, and still do. But even upper-class society is changing: Many of the "old line" families have either died off or moved away, while many nouveaux riches have moved into the area who do not share the same old-fashioned values and observe the same old-fashioned norms of behavior that the Pentlands do.
The patriarch of the family is old John Pentland. He lives in Pentland Manor, a large and old-fashioned manor house, with his sister, Cassie. Cassie is a fussy, moralistic, snobbish old maid who sticks her nose into everybody''s business and who is firmly determined to see that the Pentlands uphold the "old ways." Her companion is Miss Peavey, who lacks intelligence but in all other ways is as moralistic and disapproving as Aunt Cassie. John''s son and heir, Anson, married the wealthy but low-status Scotch-Irish girl Olivia. The couple have a son, John (nicknamed "Jack") and a daughter, Sybil. The Pentlands say that they can trace their family heritage back to the founding of the Massachusetts Bay Colony, and Anson is writing a book about the family. John Pentland''s niece, Sabine, is the black sheep of the family. Her parents died, and her home was lost to creditors. She became Aunt Cassie''s ward. But twenty years ago, she married a poor, low-born man named Callender and fled with him to Europe. John Pentland acts as if he is widowed, but about a quarter of the way through the novel the reader realizes that his wife is not dead. For the past two or three decades, Pentland''s wife Agnes has been insane, and now lives in an upstairs room in a far wing of the house. She is cared for by a nurse, Miss Egan. Every morning, John Pentland visits her and speaks with her despite her insanity. Afterward, he visits Mrs. Soames, a long-time friend of his wife''s, and plays cards. His attention to the widowed Mrs. Soames is unseemly (so Aunt Cassie says), but no one can openly criticize him for it as John Pentland is the patriarch of the family.