Odd Girl Out — Elizabeth Jane Howard

Anne and Edmund Cornhill lead an idyllic existence at their lovely home not far from London. Happily married for ten years, they enjoy a maximum of domestic satisfaction, retooling a healthy erotic life and a mutual respect for one another's autonomy. Then, one sultry summer, Arabella drops into their lives. The Cornhills open their hearts to the "lost little rich girl," whose self-indulgent mother--once married to Edmund's father and remarried six times since -- wants a holiday away from her burdensome twenty-two-year-old daughter.

Arabella proves a sweet, ingenuous, and very alluring young woman, and it is not long before she has enchanted Edmund, Anne, and even Ariadne, the family cat. But what begins as a propitious arrangement unexpectedly spirals into a bewildering tangle of love, loneliness, and excruciating longing. Soon a malevolent. cloud looms over the Cornhill household, threatening to decimate life as they all had known it.