The heir prince Zhu Yuheng keeps a secret known only to him: a mysterious poison runs in his blood, slowly killing him, leaving him just a year. Without revealing his condition, Yuheng takes on the investigation of a fire that, in a single night, erased the greatest palace in the empire from the face of the earth.
Among the blackened ruins, he finds a mechanical dragonfly and understands: this was no accident, but a carefully planned crime. The threads of his search lead him to A-Nan, a girl whose hair is adorned with an exact replica of that very dragonfly. Their meeting ends… in defeat for the prince. And now the heir to the empire becomes a servant for twelve months—exactly the length of time he may have left.
And the one pulling the strings still hides in the shadows. It remains unknown whose hand set the mechanism of death in motion.