I like the idea but fear that almost any subject worth learning would, when put in this format, have two major flaws:

1) Could deeply mislead people and corrupt their understandings of the actual material in difficult to understand (meaning difficult to detect and correct later) ways because of unintentional cultural relations. For example in your fantasy novel idea, whatever thoughts someone might attach to the relations between kings and knights might be deeply ingrained from childhood and quite a bit different than what is intended by the author of the new fantasy novel, meaning the reader could add in all sorts of incorrect ideas of their own.

2) Even though the intention is to learn the same amount of material (in this case molecular biology) by attaching it to a story, I think there is a good chance that you're actually just effectively doubling the load of material. Not only do you have to memorize the story, but then memorize the connections. Imagine learning this way and revisiting in two years, do you study the story or the material? Both? You've just doubled the amount of information you need to complete the subject in your head.