They called themselves "The Castaways". They were a close knit group of four successful couples living in Nantucket: the MacEvoys (a music teacher with a dubious reputation), the Kapenishes, the Drakes (the voluptuous Delilah married to the staid farmer Jeffrey), and the Wheelers.

The MacAvoys' marriage is strained. In hopes of settling their problems they set out in their sailboat to celebrate their coming anniversary. They mysteriously drown, leaving behind two small children. Their deaths tear the couples apart, bringing to the surface long concealed relationships and conflicts. There are questions about the deaths which must be resolved by examining all their lives.

The Castaways is a tale of relationships and friendships. The lovely Nantucket background is beautifully described. The relationships between the couples is discussed with much emphasis on the stress in women's lives.