Two bridal sedans are secretly swapped by someone in the dark, and Sui'an Eldest Princess Zhao Mingchuyu wrongly marries Shangguan Chen, son of the Grand Commandant. Facing the deadlocked situation where her younger sister has already consummated her marriage with Wei Xingjian, she simply takes the wrong with the wrong and acknowledges this marriage. Originally thinking Shangguan Chen was only a lazy playboy, after getting along she finds out that his mind is penetrating and he conceals his edge without showing it. The two go from contract husband and wife to protecting each other, and are also gradually dragged into the truth of the sedan swap, royal old affairs, and court undercurrents.