Why did a plum branch kill Li Yuanhao?

Because Wang was worried about rebelling, he killed him.

The king in the play ascended the throne by killing Guang Hai (the last king) through rebellion. When he participated in the rebellion to overthrow the unbridled sea of light, so did Li Yuanhao.

At first, Li Yuanhao thought he would be diligent and love the people, but later he found that many things he did violated his original promise of loving the people, so Li Yuanhao often gave him advice in the hope that he could become a good king. Therefore, Wang, who was suspicious by nature, began to suspect that he wanted to rebel.

Wang found a blind man to tell his fortune. The blind man felt that there would be two suns on the hillside opposite Li Yuanhao's house. As the name implies, the sun is king. If there are two suns, there are two kings. Then one is the reigning king, and the other is Sun's home at the foot of Li Yuanhao Mountain.

The king killed the blind man and tried to kill Li Yuanhao, thinking that he was the only sun in the sky. However, he forgot that (Yong 'er) was around, and the other sun that the blind man felt was not necessarily his son (Yong 'er).

Extended information about the overall plot of Plum:

Li Xi (LEE JOON GI) witnessed his father's murder because of the court coup, and his mother and sister became prisoners. He suffered from amnesia and later became the adopted son of Tieshi's family, and was named "Yong 'er".

Yong Er gradually grew into a street thug, accidentally regained his memory and began to doubt his father's death. The only clue is the sword that stabbed his father to death and the pattern on it. In order to find the sword and the real murderer, the brave man turned into a masked thief at night, leaving a red plum at the scene of the theft and turning into a famous righteous thief "Zhi Yi Mei" in the Jianghu.

A plum blossom specifically punishes corrupt officials who are rich and powerful, and fights against those in power and decadent social systems. Therefore, he became the most hated criminal of court officials and the hope of the poor, but neither the people nor the court officials knew his true life experience.

The love-hate relationship between him and his half-brother Shi Hou (Park Sihu), his first love Encai (Han Xiaozhu) and his bosom friend Feng Shun (Li Yingya) is also in full swing.