In the Prologue you play as Warrior of Light. This part of the story serves as an introduction to the story, as well as the game mechanics. It first shows how to navigate the field, then the basics of combat. Upon completing the 5 sections of the Prologue, you gain access to the ten other main parts of the Story. When you opened the first chest (stage 3) you unlock Shop. With the Prologue finishes you'll unlock the PP Catalog.