Oh I see, the border tiles. Thank's, I sometimes forget those. There will be a route continuing to the left, somewhere in the future, didn't bother to put anything there to notify the player as of this beta.
And to find the grunt, head into the museum and talk to the prof. at the entrance, after that, talk to a mountain wall in route 7, this was intended to be a little secret optional side-quest, but whatever ^^
The tile should be in the middle of two bushes.