The two still present in Join Avenue then greet you and ask what they (and everyone else in the world) should call you when at your Join Avenue.  The one on the right (presumably a girl given the giant pigtails) tells you that they’ll develop the avenue how you want, so when you’re ready, you should talk to her.

Since Join Avenue is a whole extra system and alters depending on what you choose to do to it, that will be left for a separate series of articles.  Thankfully, you can move on without doing anything else here, so if the area doesn’t inspire you, head on to the North.

Through the gate of Join Avenue is Nimbasa City.  There’s a lot to do here, but some things grab attention right away.  The first noteworthy thing is that, as you climb the stairs to the city street, you can see in the distance on the left that there ar a couple of men in what look like stylized sailing outfits, apparently barring someone’s way into a building.  Being the heroic (nosy) person you are, you should head over to the trio. 

The guy (if you’re a girl) or girl (if you’re a guy) standing in front of the two ‘captains’ explains that these are the Bosses of the Battle Subway, who turned out to be here when s/he was just trying to get in.  Fortunately (for him/her at the very least), they’re willing to battle him/her- but only if it’s a two-on-two battle.  Declaring this an ‘awesome opportunity’, your counterpart asks you to battle alongside them.  You can refuse, in which case they will decide you aren’t ready yet, and tell you to come back as soon as you are- the three will just stand here and wait for now.

Since that will sit for the time being, go ahead and explore the city.  The Pokemon Center is to the West, and a man by the front counter will gleefully give you a shard that turned up in a dust cloud while he was spelunking.  He also explains that in Driftveil City, there’s a man who will teach moves to your pokemon in exchange for colored shards- this being the Move Tutor.