Two generations of criminal policemen in Binjiang City pursued the murderer for more than twenty years, uncovering the shady story of pharmaceutical factory pollution in the industrial ruins. Criminal investigation captain Song Han and genius trace examiner Lu Shen started from the case of serial corpse burning and found that all the deceased were related to a dusty pollution lawsuit. When the investigation reaches the core of power, the "accidental death" of Lu Shen's fiancée Lin Xia, the mysterious death of the old medical examiner, and the bloody testimonies of steel factory workers emerge one after another. Finally, in the abandoned steel-making furnace, the chain of evidence guarded by two generations with their lives suddenly unfolded - in those rusty gears, there is a truth that will never corrode.
Intention: Two generations of policemen are made of flesh and blood into gears, biting the industrial behemoth clothed in the cloak of civilization on the giant chain of twenty-year reincarnation.