The story takes place in late 19th century England and Australia. Jessica Clavering has never been understood or loved at the Dower House. Her family, especially her mother, consistently talks about "better days" when they had lived in Oakland Hall, their ancestral home. But after a chance meeting with the new owner of Oakwood Hall, old Ben Madden the forbidden elderly gentleman that reportedly "stole" her family's estate,
Jessica finally feels the love and excitement that was absent in her life for so many years. As she visits Ben in secret she discovers more about her family's dark past, and how The Green Flash, an exquisite and spellbinding opal, influenced her past.
They become friends, and he puts her in his will. There is one condition: she must marry his son, Joss. She and Joss agree, but they decide to keep it "in name only". Her now father-in-law dies, and Jessica and Joss travel to their joint estate and opal mine in Australia. Here, Jessica becomes fonder of Joss and wonders if the "in name only" part of their marriage will last. There is only one problem: someone is trying to kill Jessica! Will they succeed?