Lin Xiao, a major of the expeditionary force, was ordered to escort U. S. Aid supplies to China. On the way, he was ambushed by Japanese special forces and the Burmese puppet army. He cooperated with Su Wan, a female overseas Chinese agent from Myanmar, and went around in the Yeren Mountain rainforest, where he discovered that the Japanese army was trying to use bacterial weapons to pollute the water source. Lin Xiao led a team to blow up a secret laboratory of the Japanese army, only to expose Su Wan's identity as a "double agent" - she was actually a military killer assigned by Dai Li to eliminate everyone who knew the inside story of germ warfare.
