In the small town of Hualin, at this time, taxi driver Wang Xiang (played by Fan Wei) never dreamed that he would have the opportunity to meet the person he most wanted to meet in his life and was most afraid to meet. Is it an enemy or an old friend? If you meet him, you have to give an explanation, to yourself and to your son. In the small town of Hualin, at that time, train driver Wang Xiang was in high spirits. He could drive a steel behemoth of 20 tons, but he couldn't manage the trivial family of three. The factory was crumbling and the crisis was pressing everywhere. A bag of unidentified body parts hit the water surface of the birch forest like a stone, and also hit Wang Xiang's mind. This ripple has been swinging for 20 years, until the autumn leaves turn yellow, and it has never stopped. The lost father, the dead lover, and the reunited old friend are trapped in three different eras because of an unsolved mystery, just to pursue a truth that spans the past, present, and future. When the mystery is revealed, time and space merge into one, and only the elegy of fate remains in the long season.