Qin Xiaoyue discovered that her shared roommate Xiao Yun disappeared suddenly, but because of insufficient evidence, she did not attract the attention of the criminal policeman Wen Sheng. She decided to find Xiao Yun's whereabouts by herself, but was obstructed by her friend Li Zhongping. Yun was once the lover of Ma Zheng, the boss of Marriott Real Estate Company, and she holds the video evidence of Ma Zheng's shady dealings, which is hidden beside Qin Xiaoyue, but no one can find it.

This film is adapted from a true story. In the autumn of 2001, a pair of outdoor enthusiasts discovered two elderly people in a remote and rarely visited deep forest, who turned out to be Shi Shan (played by Wang Shihuai) and Hong Gu (played by Xie Lan), missing from their village for over forty years. Living as though in a primitive society of slash-and-burn cultivation, they resided in an earthen house they built themselves, illuminated by homemade oil lamps, subsisting on their own crops, and drinking spring water from the mountain. Self-sufficient in every way, they had children and reaped steadfast devotion through the decades. Over nearly half a century, Shi Shan carved over 6,000 stone steps on the mountain with his own hands, to prevent his beloved from stumbling when she left the house, transforming from a young man with black hair to an old man with white hair. These 6,000 stone steps, known as the "Ladder of Love," invoke profound reflection on eternal love...