Following the events of the Team Meteor Base and beating Noel, the player goes in Tanzan Mountain to look for Saphira after a loud explosion was heard. Going through the now-busted left steel door, the player meets Saphira who gives them the Ruby Ring and Amethyst Pendant she took back. She then leaves telling the player to go separate ways to cover their tracks against Team Meteor, which will likely go after the defenseless Anna again for her treasure, and the player, strong enough to handle them. She also mentions Charlotte has her gym in Calcenon City.
If you head to North Aventurine Woods, you will eventually find a house filled with Pikachus. Inside is Nyu who created the PC system in Reborn. He is a bit odd, but if you give him Candies or Ice creams will give you honey in return, but if you give him Blue Moon Ice Cream, he will give you either the Heracronite or Pinsirite (you can obtain both if you give him 2 Blue Moon Ice Cream).
You can also find a Pikachu who can teach Volt Tackle to a Pikachu.
Outside the house is a place you can plant three berries as well.
If you clear the obstacles north-west of North Aventurine Woods, you will come across an entrance to a mountain. This will lead you to Celestinine Mountain. What you can do here is limited, but you can evolve Eevee to Glaceon and Crabrawler to Crabominable here and get a field note containing Icy Field.
When you put honey on certain trees, Heracross and Pinsir will later show up (by walking about 200 steps then coming back) and fight each other. Unfortunately, neither of these pokemon are catchable since they're too busy fighting for honey. Defeating one of them in battle will have the other one help you clear obstacles. Pinsir will tear down logs while Heracross will tear down spider webs. If you want to catch one of them, you must clear (almost, not all of them) every obstacle in South Aventurine Woods so you can ride a Tauros from the 3rd left entrance from Route 1 all the way to a dead end in the right of the woods. A Heracross and a Pinsir will be there fighting (without fighting for honey this time). Defeat one of them to have the other one join you.