SHUNG is born honest and simple. He is an illegitimate son. The manager of the wine factory, KOO SAI LUNG sympathizes with SHUNG and her mad mother, LAU YUK FUNG and lets them to live in the cow-shed of his wine factory. They are being looked down upon by everybody and have to tolerate any kind of abuse. LUNG gets back a collection of wine that he found problematic. He returns to the wine factory and carries out a thorough investigation covering six steps from the rice-shed, fermenting, steaming, storing, checking and filling. However, he cannot figure it out. LUNG believes that the problem is due to the steaming process. The supervisor of the steaming section, KOU, does not agree. LUNG also points out that the checking section, in charge by his brother, KOO SAI HUNG, also cannot shift his responsibility. HUNG thinks that LUNG deliberately finds fault on him. SHUNG by chance finds out that reason of why the wine has gone bad……