Autumn 1937, Hujiang Concession. The sound of gears in the clockwork conceals the assassination. Lu Yimo hid a bullet in the movement of his pocket watch and aimed it at the temple of the Major from the Special High School - click. It wasn't a gunshot, it was the sound of winding up. When the major fell down, his pocket watch was still running. This is his weapon mark law: every modified product has a unique mark, which can be traced but not caught. Shen Yanqiu, the top line of single-line communication, was arrested and imprisoned in the Hongkou Military Police. In the torture room, the soldering iron burned Shen Yanqiu's chest. He kept repeating three words: "I don't know." After the disconnection, Lu Yimo became an island. There are no files, no records, and there is no such person even in the household register of the patrol house in the concession. At the same time, Yamamoto Ichiro locked the clock shop based on the pocket watch gear number. Lu Yimo has only one last chance: to use a pen converted into a timed detonator to blow up the Japanese arsenal and achieve a victory on the frontal battlefield. But the pen needs to be calibrated down to the second—just like the watch he's been repairing for ten years.
