We have NO IDEA what it is. This was SUPPOSED to be a one-shot, but then at the last moment it was like GUESS WHAT, IT'LL BE A NEW SERIES NEXT YEAR WE JUST TROLLED YA AGAIN LOLOLOL!

So... I call it an intro, but maybe this has nothing to do with whatever they're doing later. Maybe it's a prequel. Maybe it's retconned. No fucking clue.