The warlord Amin, who held power in the north, had long harbored ambitions of monopolizing power and unifying the country. In collusion with local tyrants, he dispatched spies to the south to act as moles, with the aim of launching a massive invasion when the time was ripe. The revolutionary forces in the south became aware of this plot and sent Tang Huang to the north to gather a list of the spies. Posing as a student studying abroad, Tang Huang carried out his mission but encountered unexpected challenges along the way.