Interesting how writing about relationships between characters can feel so personal, and yet at the same time make me feel insecure. I think by Book 5 of course the relationship between Sergeant Michaels and Portia will have had to change. I mean, the girl has solved 3 cases that he has been involved in, and she has to have at least gained his grudging respect if not a tiny amount of admiration, but when can it move into reliance?
That might not even be the right word. What would you call the relationship between Holmes and Lestrade? Inspector Lestrade came to Holmes on cases that he found impossible to solve right? So that is a dependence of some kind. And Holmes relied on Lestrade for some of his more interesting cases, and access to mysteries that he might not otherwise have been allowed access to.
Up till now, the relationship between Portia and Michaels has been one of requirement for Portia and one of annoyance for Michaels. I think for her to truly become a consulting detective, she now has to become sought after by the Yard.
I think the best way to unite these two so Portia can get past her arrogance and Michaels can get past his disdain for someone pursuing a Holmesian-career is to give them a common enemy. Someone like Mycroft perhaps?