Adapted from The Song Dynasty's Lady Assassin, the drama follows Mei Jiu (An Jiu), a quirky girl with dual souls, who joins the Crane Guards to find her missing mother. As An Jiu, she meets Chu Dingjiang, a young general weighed down by secrets, and together they fight through life and death. As Mei Jiu, she crosses paths with Hua Rongjian, a charming noble who falls deeply for her. Together with fellow agents—proud heiress Mei Tingyuan, medical genius Mo Sigui, and vengeance-driven Lou Mingyue—they grow and transform amid family feuds, national turmoil, and youthful passions.