In a coastal village where mermaid tears become precious pearls, young Hai Shi witnesses her father’s death during a brutal pearl-harvesting ritual. Blaming the emperor for her suffering, she vows revenge. When she crosses paths with Fang Zhu, a powerful court official and the emperor’s closest ally, he offers to train her—on one condition: she must disguise herself as a boy. As Hai Shi rises through the ranks of the royal military, the kingdom teeters on the edge of collapse, held together only by Fang Zhu's strength. Torn between loyalty, love, and vengeance, Hai Shi must navigate dangerous court intrigues and the secrets that could change everything.