The story of pt 2

I am confuse because there are two "The Story of", one in the beginning and ending. However, the second one seem to continue from the part 1 and there some changes how Norma met Dirty Norma. Also some scenes repeat, when she called the hotline. To me, I feel like the second one gives more details on characters and stories, such as epilogue on some scenes. While reading it, I have some questions, why did she brings back the same story? Is it kind of continuation of story? and  Why she use it in beginner and ending?