A female soul from modern times awakened in the troubled times of the Republic of China, only to find herself trapped in the body of a twelve-year-old boy named Lin Yan. When he first woke up, he saw his family being slaughtered by warlords.
With a huge sense of torn apart and deep-seated hatred of dual identity, he or she fell into the abyss of Shanghai alone. With wisdom and insight beyond the times, he worked step by step in the bloody arena of the underworld, using the "undercurrent" as his banner to establish his own laws and empire.
However, personal ambition and hatred eventually become insignificant in the face of the tide of the times. When the Japanese invaders trampled the mountains and rivers with their iron hooves, he had to make a choice: should he continue to be a hero of the separatist regime, or become a messenger carrying fire in the dark night?
