Why did Gu Haitang's father disappear?

Gu Shunqi, the father of Gu Haitang, died by the sword of Shi Jizhou. In the drama "Haitang Drinks Rouge through the Rain", Shi Jizhou and Gu Shunqi had an argument. In their entanglement, Shi Jizhou knocked Gu Shunqi unconscious, while Lang awakened Gu Shunqi, but was discovered by Shi Jizhou when he escaped. Then Shi Jizhou hacked Gu Shunqi to death and Lang fell into the lake.

Gu Shunqi is the origin of the story "Begonia Drinks Rouge through the Rain". Gu Haitang went to Lang's house to find his father's whereabouts, and only then did he know Lang and all the stories that followed. When Gu Shunqi received the notice from Lang's family, the result was gone forever, and there was no news for many years. With the disappearance of Gu Shunqi, the family also lost their laughter. After Gu's mother died, Gu Haitang came to Kunyang to investigate the mystery of his father's disappearance.

Later, Gu Haitang met Lang Xuanyue, the second son of Lang family, and went to work in Lang family. Gu Haitang, who works in Langjia, gradually discovered the truth of his father's disappearance.

It turns out that Gu Shunqi's disappearance has something to do with Lang Xuan Yue. At that time, Gu Shunqi took a little boy to escape the chase. He gave his daughter Gu Haitang a birthday present for the little boy to keep. After that, Gu Shunqi took the enemy alone. This little boy was Lang Xuanyue who was later adopted by Lang Sinian. It's just that he lost his memory when he fell into the lake

Later, Shi Jizhou inadvertently revealed the truth about Gu Shunqi's disappearance. It turned out that when Lang was a child, he witnessed Shi Jizhou kill his mother for the recipe. The frightened Lang Xuanyue hid in the closet and saw Shi Jizhou arguing with Gu Shunqi. After Gu Shunqi was knocked unconscious by Shi Jizhou with a vase, the frightened Lang Xuanyue came out to wake Gu Shunqi and told Gu Shunqi that Shi Jizhou had killed his mother. Gu Shunqi fled with Lang Xuanyue, but was unfortunately discovered by Shi Jizhou, who killed him. Xiao Lang Xuan Yue accidentally fell into the lake when he escaped and lost his memory.