At 17, Jessica Clavering yearns for a life of excitement and romance. So when a rough Australian opal-miner buys her family's decaying ancestral mansion, she defies their orders and befriends him. From him she hears of the finest opal of all - the legendary green flash.

Jessica only realizes how little she knows her "family" when she starts a relationship with the forbidden elderly gentleman that reportedly "stole" her family's estate. 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.