In 1947 Doornfontein, South Africa, an elderly Lesley sits on her stoep at sunset, pouring a glass of wine for herself and one for her late husband Robert, as has been her ritual since his death. She has spent the day immersed in memories of Penang—of Arthur, her brother, Sun Wen, and especially the two weeks Willie Maugham stayed at Cassowary House. A copy of Willie's The Casuarina Tree has just arrived in the post.

Lesley reflects on her difficult adjustment to the bleak Karoo, where she eventually found peace and learned the southern constellations. Robert's health recovered, and they grew close again, riding together across the farm. She recalls one morning when they encountered a pair of ostriches, which Robert likened to cassowaries.

When The Casuarina Tree was first published, it angered Penang society but spared Robert and Lesley the worst exposure: Willie did not write of Sun Wen or her affair with Arthur, only fictionalizing Ethel's story in 'The Letter.' Reading it prompted Lesley to ask Robert about Ethel's cryptic remark, 'He made me do it.' Robert reveals a long-kept secret: Ethel's lawyer Pooley told the High Commissioner that William Proudlock had been blackmailing Steward over Ethel's affair, and when Steward turned the tables, William coerced Ethel—with her father's complicity—to lure and kill Steward, threatening divorce and abandonment if she refused. Robert had advised that nothing could be done without her confession. Lesley also learns Ethel was illegitimate and possibly Eurasian.

Lesley summarizes the years afterward: Sun Wen died of cancer in 1925, having remarried; Willie recovered financially through The Casuarina Tree's success, divorced Syrie, and settled at Villa Mauresque. Robert died of a heart attack in 1938 and was buried on the farm with a Horace inscription, having asked her to return to Penang. Her son Edward became a KC; her son James, a novelist, was killed in Malaya during the war. Geoff also died in the war.

That night, rereading 'The Letter,' Lesley feels she is floating through Cassowary House once more. She studies Willie's Moorish symbol in the book and notices new ink lines added by another hand—forming the doors of the House of Doors. She realizes Arthur, after nearly forty years of silence, has sent her a coded message. Resolving to answer it, she plays Hahn's L'heure exquise on the piano, then steps into the starlit night, determined to write a letter to Arthur and to begin new stories of her own.