You were on your way to Turrfield after registering for the Gym Challenge, and had to go through the Galar Mine to get there. It wasn't too much of a hassle to weave through the mines, fighting Pokemon or trainers you bumped into along the way. You would have been in and out in a couple minutes, but as you approached the end of the mine...

"You." A voice spoke from behind you, sounding vaguely familiar, but not quite.