When a prude housewife’s perfect son goes missing, his secret life as a gigolo is revealed and the mother decides to pose as a prostitute in order to infiltrate the underground world and find out what happened to her son.

I like Tor Dollhouse's suggestion. It gets right to the heart of the matter by using fewer words.

Thank you both so much for your comments :D I can definitely see what you're saying!

This tells us the story but is rather 'clunky' in the sense that it seems to feel like it goes 'and then...and then...' I think the start is fine but needs altering as it goes down.

When a prude housewife's son goes missing she uncovers his secret life as a gigolo causing her to infiltrate his dark life to uncover the mystery by posing as a prostitute.

This would be my first attempt at it which says the same thing but in less words. Still think my version can be tightened but this is the information to get across I think.