Ten years ago, Prince Pei Jue (Duke of Qin) and Bai Ling'er, daughter of the Grand Chancellor, fell in love on the battlefield. Three years later, Ling'er died saving Pei Jue, revealing on her deathbed that they had a daughter—Xiao Yueya—lost to the world. The grief-stricken prince abandoned his title to search for her. Meanwhile, Ling'er's ambitious younger sister, Bai Yao, also sought the child, both to uncover her sister's mysterious death and to secure her family's power. Fate intervenes when Bai Yao and Xiao Yueya, pursued by assassins, are saved by Pei Jue. A broken jade pendant proves the girl's identity. To protect his daughter and investigate Ling'er's murder, Pei Jue enters the Bai household as a ""bodyguard,"" entering a marriage of convenience with Bai Yao. Upon returning to his estate, Pei Jue finds his family usurped. When his grandmother takes her own life to spare him political strife, he severs all ties to his past and fully commits to the Bai family. But danger lurks within: Bai Ce, Yao's cousin, conspires with outsiders to discredit her and Xiao Yueya, aiming to seize control of the Bai clan. Each scheme is thwarted by Pei Jue’s cunning. The true mastermind emerges—Marquis Shen Qingshan, who once orchestrated the attack on Pei Jue and now plots with foreign forces to overthrow the dynasty. He manipulates disgraced scholar Wang Zi'an and Bai Ce to sabotage Bai Yao's leadership of the Tianji Pavilion’s machinery division, all while his sister, the empress, poisons the emperor and invites invaders across the border. In a final gambit, Shen orders Wang Zi'an to kidnap Bai Yao, demanding Pei Jue’s suicide. But fate defies him: though the emperor falls, Pei Jue survives. News of the undefeated ""Ghost of the Battlefield"" terrifies the invaders into surrender. With the conspiracy crushed, Pei Jue executes Shen—and at last, the phoenix rises from the ashes.
