OK, so I decided to give it a go after I replied to Aesica below. But basically, if you talk to your party, it will progress the game to the next map. Then, after the cut scene, you'll need to navigate to the top of the mountain in this invisible state until a boss fight. In the beginning, the controls seem weird and like you could be stuck, but it's possible to reach the top. This will be followed by the last boss fight and cut scenes (no more traveling, fortunately). I just completed the game :)