The Disappearance is the incident in which Gym Leaders are being kidnapped, leaving behind no trace or clues. There are a few official investigative teams, and you don't need to be part of them at all. You're just a trainer on your journey.
However, several trainers have begun to find themselves uncovering clues about the Disappearance, and one trainer recovered the Gym Leader Misty, though she had no idea who had taken her and she had been in a pitch-black cell.
The Disappearance is a very active topic between trainers. The most popular investigative team, who have progressed the furthest, is very admired and contains very notable members, such as Cheren.
We will keep a list here of Gym Leaders and their status, as well as updates.