Monkey and the others become involved in the story when the daughter of the magistrate and the dog demon chooses to live with her mother instead of her father - who hates her - but the father sees her disappearance as a kidnapping and blames Pigsy and Sandy. This mistake is rather more understandable in context, as the dog spirit followers of the Dog-Woman have sent the father a ransom demand.
Anyway it all gets sorted out by Monkey. Tripitaka gets himself captured by the Dog-Woman, who then plans to marry him as part of her efforts to turn her daughter as evil as she is herself. Monkey interrupts the wedding by substituting himself for the unwilling groom.
The guests at the wedding are the dog spirit minions, who can look human but when changed into their true form look particularly silly.
Suffice to say Monkey defeats the dog spirits, but when he is about to kill the Dog-Woman, her daughter begs Monkey to spare her, and this so disgusts her mother that she disowns her. Fortunately the magistrate has seen the error of his ways and takes his daughter back.
This is a fairly average Monkey episode, on the whole.