CeCe D'Aplièse has always felt like an outcast, and following the death of her father, Pa Salt, she finds herself more alone than ever — so she decides to unravel the mystery of her origins. The only clues she has are a black-and-white photograph and the name of a female pioneer who once lived in Australia.
On her way to Sydney, CeCe stops in Krabi, Thailand, where her fate becomes entwined with the family of Mrs McCrombie, including twin brothers Drummond and Andrew, heir to a pearling fortune. When CeCe reaches Australia's Red Centre, something in her responds to the land and the ancient culture of its Aboriginal people, and as she nears the truth of her ancestry, she begins to believe this untamed continent could offer her a sense of belonging.
The novel also follows Kitty, beginning in 1906, the daughter of a philandering Scottish minister who travels to Australia and marries into a German-Australian pearling family — her story converging with CeCe's across a century. The Pearl Sister is the fourth novel in Lucinda Riley's Seven Sisters series.