This is an intensely tragic romance that transcends life, death, and imperial power. Two years ago, the young Xie Yun climbed over a wall into the courtyard and promised Zhang Heng that he would give her the grandest coming-of-age ceremony. Two years later, Xie Yun returned after narrowly escaping death countless times, only to witness his beloved, dressed in plain white, enter the imperial palace to participate in the selection of imperial consorts. The imperial palace is as deep as the sea, with deadly traps at every turn. The Crown Prince regards the child in Zhang Heng's womb as a thorn in his side, repeatedly devising poisonous schemes and attempting to kill the unborn baby under cover of darkness. Xie Yun patiently plots in secret, sacrificing his military insignia and relinquishing his military power in exchange for a slim chance of survival for mother and child. Zhang Heng endures hardship alone in the Cold Palace, giving birth to a prince named Chang'an and devoting everything to protecting him as he grows up. As the imperial court becomes increasingly treacherous and powerful maternal relatives stage a military coup to seize the throne, Xie Yun dons his armor, suppresses the rebellion, and fights a bloody battle to secure the empire.