Underground boxer Zhang Ning (Xia Yu) and his girlfriend Sun Jing (Charlie Yeung) are on the run from the relentless pursuit of four cops as well as a pair of merciless bounty hunters out to get them. What happened? A year ago, desperate for money to please Jing, Ning accepted the job to kill a man in Hong Kong. He then fled to the Mainland, where the police has dispatched four elite cops (Wu Jing, Duan Yihong, Ni Dahong, and Zhang Li) to investigate the case. They traced the fugitives to the unforgiving environment of the wild, wild west of China. Meanwhile, Ning's mysterious client (Tse Kwan Ho) learns that Ning possesses his criminal evidence, so he hires a couple of top hitmen (Francis Ng and Yu Nan) to silence Ning for good.