The movie plot of The Golden Lock

Dissatisfied with the darkness of the imperial court, Dr. Cai Yixiu resigned and returned to Li. Before leaving, Dou Shangshu betrothed his daughter Su E to his son Changzong, and wrote down the golden lock. Yixiu died after he returned to his hometown. More than ten years later, Chang Zongkao was admitted as a scholar, and his mother went to Beijing with her hometown Cai Yi to meet her son. Cai Yi left to find an old woman's second aunt, her son and donkey to help with the housework. Dou Shangshu suspected that the Cai family had fallen, and had already married his daughter to Cui. Su E was dissatisfied with his father's breach of contract, so he disguised as a man and went home with Cai Yi to marry Changzong. The donkey coveted Su E's beauty, conspired with his good friend Lv Sanhe to steal the golden lock, and pretended to be Changzong to ask Dou Shangshu for a wife. Dou Shangshu was tricked into giving money under the threat of Lu Sanwei and appointed him as the county magistrate. After Lu San became a local official, the donkey tried to falsely accuse Changzong of being a thief, but failed. Chang Zong and Cai Yi were pushed into the water and drowned on their way to Beijing to take the big exam. The donkey even poisoned the sheep's intestines, trying to poison mother Cai, but killed her second aunt by mistake. The donkey sued Cai's mother for poisoning and the county magistrate Lu San. Su E couldn't bear the torture of Cai's mother, confessed the crime and called Lu San a traitor. Lu Sanyi angrily sentenced Su E to behead. On the day of execution, it was raining and snowing, and Chang Zong suddenly appeared. It turned out that Changzong was saved by his fellow villagers and returned to his hometown in high school. When he learned that Su E had been wronged, he went back to my official for retrial. Lu Sanhe and Donkey were severely punished, and he and Su E were finally reunited.