Just finished part 5, and wanted to say a few words before moving onto part 6.
Firstly, the character development is REALLY working. We needed the history and the difficult moments to draw us in, to help us see and understand who these people are, so we could understand and cherish what they are starting to learn and see about themselves and between themselves. The sense of a major emotional hurdle, a massive emotional problem to consider is very real.
They are "sisters", but only in the legal sense, not in any form of biological sense, so in that manor there is no reason for them to resist their growing attraction. Of course that is a coldly clinical statement, and simply ignores the massive emotional elements that "disprove" that, long before you consider the emotional mess of their parents ever getting wind of all of this.
So that was very well done, tender, moving, delicate and sexy, it worked really well, felt natural and moved things along very nicely
Then back to the sex shop, seeing them so unable to go through the door, that really made me giggle, so "back to normal", not that that lasted long at all!
The experiences in the sex shop though, talk about a serious role reversal! I do wonder how much encouraging is coming from the shop keeper, and how much she is simply helping and guiding what is naturally happening and taking place here. Back to being mean... WOW, priceless moment, but at the same time, we have always known that her sister has a serious submissive side, it just takes a different form and shape is all.
The ending though, that tied things together very well, the massive contrast between the warmth of the mother / daughter and the frigid and rigid coldness of the father / daughter, it shows so much about how these people came to be the people that they are...