Is this a good concept

I am working on my first real book it’s gonna be a dark mature partially legal drama. It’s gonna be about a morally gray man who is getting a divorce. his wife has a daughter she is 16 now but she was a year old When they got married. He never legally adopted her so now he is trying to get custody by any means necessary even illegally. his wife is a selfish person who puts her career above everything which is why they are getting a divorce and for authenticity I am using r/legaladviceofftopic.