The late emperor passed away, and Shu Chu, a concubine who had just entered the palace at the age of fifteen, was about to be sent to a temple because she had no heirs. At this time, she met the newly appointed king, Ling Yao. They were a mother and son in name only, but Shu Chu was one year younger than Ling Yao. This, coupled with Shu Chu's charm, made Ling Yao fall deeply in love with her... But no one thought that the virtuous, gentle and considerate Concubine Yan Hui (Shu Chu) was actually an elite assassin in the assassin team. She entered the palace just to kill the emperor. Will he, who loves Shu Chu, accept the fact? Could things be so simple? According to legend, the beauty of the butterfly attracted the gods in the sky. In order to punish the mistake, the emperor shortened the life of the butterfly. The life of the poor little butterfly was shortened, so that it could not be with the person it loved for a long time. In order to take revenge, the butterfly did an unforgivable thing, but behind this incident, the butterfly did not just do it for the word "love". Everything in the world, whether it is a human or an animal, will always experience the word "love" in life.