Gu Zhaoning, the legitimate daughter of the Marquis of Dingyuan, has been deeply in love with the Crown Prince for five years. Yet at a flower-viewing banquet, she finally sees through his favoritism and misunderstandings, and decides to sever her old attachment. Having regained her clarity, she no longer confines herself to romantic entanglements. Instead, she investigates a series of long-buried cases and gradually forms an alliance with Xiao Linyuan, the cold and formidable Prince Regent. From testing each other to joining forces, from investigating cases side by side to protecting one another, they gradually uncover the truth. Through countless choices, they come to understand their feelings for each other, leave the old schemes behind together, and embrace a happy ending of their own.