19th-century East Coast. Grace, an oyster-harvesting girl, is the stepdaughter of the reclusive pearl master "Golden Eye"—gifted beyond measure, yet forbidden by her grandmother to ever gamble on pearls.
Alex Miller, second son of the Miller family, hunts for Golden Eye to reclaim his inheritance. Grace sees through shells at a glance and quietly guides him to a blue-white pearl. When loan sharks threaten her family and her grandmother collapses, Alex pays the debt and medical bills. Grateful, Grace breaks her rule and helps him again—yielding a rare tea-gold pearl.
At the Lanxi Bay auction, Grace searches for her mother's keepsake—a Queen's Conch. Her cousin Leonard, manipulated by the villain Carter, bids $300,000 for it—only to find it dead. Grace buys the shell cheaply and extracts a priceless conch pearl. The trail points to the Miller family's uncle colluding with pearl tycoon Carter—and to her mother's murder.
Her stepfather Owen is kidnapped by Carter, refusing to serve him even at the cost of his eyes. Grace heads to Saint Kui Port, helps Lady Grant expose a scam, and earns a general's token. At the pearl convention, Carter's son Kane tricks Alex into massive debt—Grace gambles with her unmatched eye, wins enough to clear it.
To end the feud, Grace challenges Carter to a life-and-death gamble—staking her life and all assets. Carter cheats and kidnaps her grandmother, but Grace keeps winning—peacock-black pearls and rare Melo pearls. With General Grant's support, she wins the century gamble. Carter flees, is caught, and takes his own life—revealing: her mother's true killer is someone close to her, tied to the Miller family.
Grace donates Carter's empire to charity. The revenge is unfinished—the killer unknown. She and Alex stand by the sea, vowing to uncover the truth.
