When an American cop witnesses his mentor's murder in a trade deal gone wrong, he finds himself on the wrong side of the law in Thailand. But despite the bounty on his head and pressure to leave the country, he teams up with an ex-military mercenary out to settle a score of his own to bring the killers to justice. Their quest for vengeance brings them face-to-face with a band of notorious criminals who vow to take them down if the jungle's natural elements don't kill them first.

In the 1930s , a Japanese cult called The Temple of Hades was ordered to cooperate with the Japanese military to destroy China. They buy so many young children from poor family , who will be trained as a lethal killing machine and serve the Empire of Japan. One of them is Vajra , who was forced by his captors to fight for the food , and accidentally causing the death of his brother. Several years later , Vajra grown up and become one of the biggest killer in the Hades sect. Vajra escapes to China and joins Shaolin , where he receives spiritual enlightenment and determined to support China against Japan.