Concubine-born Su Yunzhao, to protect the hostage Nanny Gui, is forced to marry into the Jing Manor in place of her legitimate elder sister, a manor rumored to belong to a Prince Jing whose legs are paralyzed and whose temper is violent. Skilled in medicine, she discovers after entering the manor that Prince Xiao Jingheng's disability is actually a disguise caused by long-term poisoning with paralytic bone-rotten grass, and the two form an alliance. While navigating inner courtyard struggles and exposing fake pregnancy schemes, Su Yunzhao investigates the old case of her biological mother being poisoned and killed, unearthing the mastermind behind the scenes. As the old subordinates of the Northern Expedition Army and the secrets of the military tally gradually emerge, court turbulence abruptly rises. Together, they break through frame-ups, unravel years of conspiracies, and clear their grievances. Ultimately, they tear up the pre-nuptial divorce agreement, stand shoulder to shoulder at the pinnacle of power, and establish new regulations to protect their home and country.