Xiao Qingge, a princess from the Southern Kingdom who is an expert in poisoning and medicine, married into the Northern Kingdom for her mission, but she encountered a coup in her home country and her father was imprisoned, making her an abandoned son. In the crisis-ridden Northern Palace, she tested, exploited and formed an alliance with the seemingly weak but ambitious third prince Yu Wenyi.
Xiao Qingge used poisonous and medical skills to maneuver around the harem, while Yu Wenyi used his illness to gain strength. The two worked together to eradicate political opponents and uncover secrets such as the power struggle in the North, the treason of powerful officials in the South, and the Xiao family's annihilation. When the righteousness of the family and the country are intertwined with personal grievances, and love and power collide, Xiao Qingge struggles with revenge and redemption. He must not only deal with enemies in the north and south, untie the bond with Yu Wenyi, but also keep his heart in the power game.
