A young maniac starts a terrorist spree in Hong Kong. The police do not manage to catch the culprit. When the wife and child of inspector Tsui get wounded in one of the explosion, he intends to catch the dangerous maniac.

Sergeant Kwok Wah (Andy Lau) and Ho Lung (Ray Lui) are both colleagues and best friends. Ho Lung has developed hatred with a gang leader Dick. Dick sends Hung (Cherie Chung) as a bait to kill Ho Lung. Swore to take revenge for his best friend, Kwok Wah works with Ho Lung's partner Mother (Kent Cheng) to unveil the enemy. Kwok Wah saves Hung during an operation and Hung starts to like Kwok Wah. Kwok Wah and Mother follow their plan to capture Dick, but it ends in vain and both of them get into a gunfight. Hung is killed for saving Kwok Wah during the gunfight. Though heart-broken, Kwok Wah and Mother go on fighting the villain...