Even though it is set in a summer colony in Maine, whose residents believe that civilization ends just south of the Princeton campus, COLONY is similar to earlier novels by Anne Rivers Siddons, such as PEACHTREE ROAD (1988) and OUTER BANKS (1991), which are set in her native South. Like those works, COLONY tells the story of an outsider confronted with a highly structured society which does not intend to permit individual differences.

The outsider in COLONY is Maude Brundage Gascoigne, member of an old Charleston family, who meets and marries a Bostonian, Peter Williams Chambliss. As soon as the new bride arrives at Retreat, the summer colony in Maine where the family always gathers, she learns that her marriage will not be easy. Her mother-in-law makes it clear that Maude will never be right for her son, his family, or her society.

Soon, however, Maude comes to realize that although she has the misfortune to be a foreigner, all of the young wives are living in a condition of enslavement. They are expected to be servants to their husbands, their children, and above all, to the matriarchs who rule the society, until they themselves become old and claim the rocking chairs on the club veranda. Maude, however, does not merely endure; during her lifetime at Retreat, she preserves her identity and displays a moral integrity which earns her the respect even of her mother-in-law. At the end of the novel, Maude makes her final contribution to the place she has come to love by transmitting to her granddaughter the right to own it and the responsibility to preserve it.