Spoiler warning!
This is my chapter by chapter summary of the Prologue. The Prologue refers to the first six chapters before the major choice is made. Please note this is based on the Japanese version of the game.
The story from there branches to Hoshido, Nohr, and Touma/Invisible Kingdom (the third path). Links to those sections can be found at the bottom.
This was all done on my free time, and so took a while. It was certainly a lot of work, but I do hope you enjoy! I am unemployed… so please consider donating if you like the work I do. : )