Prologue - End or new beginning?

This story tells what happened to Ash after returning home from Kalos.
Ash Ketchum is not the kind of coach who comes down after a defeat... or yes?
His latest journey has been constantly haunted by memories. Now that he is sixteen, he is frustrated with the idea that he has not yet become a Pokémon Master.
Does Ash intend to drop everything?
It takes something to remind him who he really is... or rather, someone.

Special chapters:
- Necrozma and the Ultra Space
- Poipole and other Ultra Beasts
- Lunala and the protectors of Alola
- The return of Mew