Baosi was one of several dancing girls given to King You, last emperor of the Western Zhou dynasty. The emperor was used to sycophantic concubines vying for his favors. Therefore, he was fascinated by Baosi's cold look of indifference, and made it his mission to elicit a smile from this ice maiden. He went as far as to dethrone the empress and put Baosi in her place, but to no avail.
In the capital city was a beacon, to be lit in the event of an enemy attack. One night, in an attempt to amuse his favorite, the emperor ordered the beacon be lit. Thinking it was an attack, the dukes and marquises gathered up their armies and rushed to defend the capital. The people inside the city were safe, but those living outside were thrown into mass confusion. When Baosi saw this, she was delighted and smiled. Much pleased, the emperor told everyone to go home, there was no attack, that he had only wanted to make Baosi smile. From that day on, the beacon would be lit from time to time, with the same outcome. After a while, the dukes and marquises got tired of being ridiculed and stopped responding.
Not long afterward, the father of the deposed empress mounted an assault on the capital. The beacon was lit, but no one came. The emperor was forced to flee the city with Baosi, only to be captured and put to death, bringing about the end of the Western Zhou dynasty.