The pearl sister:

The Pearl Sister is the fourth book in the number one international bestselling Seven Sisters series by Lucinda Riley. CeCe D'Apliese has never felt she fitted in anywhere. Following the death of her father, the elusive billionaire Pa Salt - so-called by the six daughters he adopted from around the globe and named after the Seven Sisters star cluster - she finds herself at breaking point. Dropping out of art college, CeCe watches as Star, her beloved sister, distances herself to follow her new love, leaving her completely alone. In desperation, she decides to flee England and discover her past; the only clues she has are a black-and-white photograph and the name of a woman pioneer who lived in Australia over one hundred years ago. En-route to Sydney, CeCe heads to the one place she has ever felt close to being herself: the stunning beaches of Krabi, Thailand. There amongst the backpackers, she meets the mysterious Ace, a man as lonely as she is and whom she subsequently realizes, has a secret to hide . . .