In the autumn of 1942, deep in the Taihang Mountains, there was the Jingxing Coal Mine.
Ma Yanfeng, a coal mine accountant whose left foot drags the ground slightly as he walks, commutes between the walnut orchard and the mining area every day. The villagers called him "Er Fool", but no one knew that he had another name - "Lai Ting".
Xu Long, a truck escort with a scar on his face, comes from Yangquan and appears on the Shitai Line every once in a while. He also didn't know that Xiufen, the woman who was lighting the fire at the kitchen door of the cafeteria, was looking forward to his return every day.
They communicated on a single line, up and down, and had never met each other.
On the day that Nanguan Grocery Store was sealed, the intelligence network was shut down. Ma Yanfeng had only one last resort - leaving a letter with only four words in the crack in the wall of the Wang family compound:
"A letter is like a meeting"
