Two men, one a businessman skilled in Kung Fu, the other a kickboxer discover they are brothers, and together, both in and out of the ring, they must face a crime syndicate. One of the first films to use the martial art of Muay Thai.

The Angry Guest is a direct sequel to Duel of Fists which had two long-separated brothers, Ti Lung and David Chiang, reuniting in Bangkok and running afoul of the local mob after Ti Lung, a boxer, beats the local favorite in the ring. In this film, the action shifts from Bangkok to Hong Kong to Japan and then back to HK as the brothers contend with a Japanese mob led by crime boss Yamaguchi, who is played by the film's director, Chang Cheh, in a rare screen appearance.