In MARDEK, Missable Content is any item, event, or other collectable that can be permanently lost after a certain point. Each chapter of the MARDEK series (A Fallen Star, A New Hero, and Keystones) has a point of no return: once the player passes it, they will be unable to return to any other part of the chapter. Additionally, the player cannot load a save file from one chapter in a previous chapter; this includes files saved at the end of a chapter.