Lan Shuang takes the old hairpin and rushes to the border to find her missing fiancé Lu Yan; the border general Shen Que suspects that she is a trickster and makes things difficult for her; the old hairpin's hidden map points to an abandoned beacon, and the two are forced to go together to investigate; on the way they encounter horse thieves and court spies, and discover the beacon. There are secret letters from the previous dynasty hidden in the suit; the secret letter reveals that Jiuchai is related to the border military salary embezzlement case, and Shen Que's family is implicated; Lan Shuang learns from the secret letter that Lu Yan has appeared here, but the trace has been broken; Shen Que begins to trust Lan Shuang, and the two work together to investigate; Bian Shuang The situation is tense, and Beidi is ready to make a move; Lan Shuang's identity as a man disguised as a man is about to be revealed; the material of the old hairpin is related to the Beidi royal family, burying a bigger mystery; one of Shen Que's lieutenants is acting suspiciously; they are trapped in the beacon on a snowstorm night, and Lan Shuang is injured Shen Que After taking care of her, she discovered that she was a woman; the mysterious man in black sent a second hairpin and a message from Lu Yan; Lan Shuang was so confused that she decided to go to Beidi to search; the early stage of the story established conflicts and temptations, the middle stage revealed the line of life and treasure, and the late stage decisive battle and emotional destination
