Once you defeat Lenora, Hawes will run in and say that Team Plasma are threatening to steal the Dragon Skull. Head back through the library and out into the museum, where you will witness several Team Plasma Grunts using a smoke cloud as cover so they can steal the Skull. Lenora will chase after them, and so should you, so head outside. Once there, a man comes up to Lenora, who introduces him as Burgh—the Castelia City's Gym Leader. Soon, Bianca and Cheren will show up and everyone splits up to try and track down Team Plasma; you will be partnered up with Burgh and the two of you will need to search Pinwheel Forest.
Walk west of Nacrene City and you will find yourself on a paved road leading to the Pinwheel Forest. Approach Burgh and he will go inside the inner portion of the forest. It is here that you have a choice: either follow Burgh into the inner forest, or go south to battle Trainers and wild Pokémon to gain some Exp.
A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
Once you have gained some Exp. follow Burgh through the trees and into the inner portion of the forest.
Inner Portion
Once inside, head west, then north and talk to Burgh. He will go ahead and block the northern exit of the forest, leaving you to go along the forest path and find the Team Plasma members who took the Dragon Skull.
A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
Walk west onto the forest path, then go south, followed by west again, battling Trainers and Team Plasma Grunts as you go. You will find yourself in a large area with several patches of tall grass. Go west and battle another Plasma Grunt. There is a Pokémon Ranger standing in the tall grass in the northwest corner of the area. You can battle him if you want, although it isn't necessary. Go west and head through a gap in the fence. Walk along the path of tall grass and battle the Youngster here. Continue following the tall grass path and walk north through a hollow log. As you walk north, you will notice a second log and a Plasma Grunt above you. Make you way through the tall grass to your left and head up the log and battle the Plasma Grunt. Go through a second log, then head east until you see yet another log. Go through that and you will confront a Team Plasma Grunt. After you defeat him in battle, he gives you the Dragon Skull and suddenly a man in brown and yellow robes will appear. He is Gorm, one of Team Plasma's Seven Sages. Gorm reveals that the Dragon Skull did not belong to the right Template:Type2 Pokémon. Soon, Burgh and Lenora will appear and after a chunk of dialogue, Gorm and the Grunt disappear. Now, Burgh will return to his Gym and Lenora takes the Dragon Skull back. As a reward for recovering the fossil, she gives you a Moon Stone, which can be used to evolve certain Pokémon, for example: Munna into Musharna. Once Lenora leaves, you can go west back onto the main path and leave Pinwheel Forest via the northern exit.
Once you leave the forest, you will find yourself on an observation platform of some sorts. Go through the gate (the entrance to which is to the east of the observation platform) and you will arrive on Skyarrow Bridge. Like every other bridge in these games, Skyarrow Bridge is a cinch to cross. Just keep running north until you reach the other side. Once you have done that, you will arrive in Castelia City!
