There are actor combinations that work & some that falls rather flat. Shaw Brothers has a rich history of employing such tactics starting with David Chiang & Ti Lung. We later see Fu Sheng & Chi Kuan Chun and then Fu Sheng with Ti Lung. But director Liu Chia Liang found the right spark of chemistry between Gordon Liu & Wong Yu.
In what is unofficially their 5th pairing together, the film centers around the 11th prince (Gordon Liu) who eventually is in route for the naming of the successor to the king. He befriends (or more like tricks) a street con artist (Wong Yu) into being his disciple through a poisonous injury that only the prince can cure. This is how we get the title of the film by the way although it actually translates to Rotting Head Ho (guess that title would have been a turnoff in the US. Left with no choice in the matter, the con artist closely follows the prince as his student while several attempts on the prince's life are made by assassins hired by the jealous brother of the prince. The prince ends up training the disciple as they embark on their journey to the capital for the ceremony for the successor again amid killers thwarting their efforts.
The interaction between Gordon & Wong is priceless & well worth the price of admission. Gordon is very proficient in his fighting & Wong holds up his end as well. Among the assassins are familiar faces such as Wang Lung Wei, Hsiao Ho, Wilson Tong & Lo Lieh. Also Hui Ying Hung has a cameo that plays a vital role in this. The fight choreography in this movie is rather impressive, especially the "fights meant to look like that weren't really fights".
My only cause for pause in the movie was the nonsensical scene with the 7 bitters which was kind of offputting, but I guess that's humorous in their culture. Nonetheless you will enjoy this film greatly if you're a kung fu fan. A must see!