Driftveil City (5th Gym)

Before you even reach the city, you will see black and white-blue costume Team Plasma talking.. The black costume will then leave when your rival arrived.. You will then be asked to go to the white-blue/Old Team Plasma's hideout.. It's located north-east of the city, or rather "above" the gym.. You won't be able to enter the gym till you go through the event.. Once you have reached there, you will have to battle with Rood, who's one of the sage of the old Team Plasma.. Once you have beaten him, go into the house and you will hear about the story between these two teams.. After that, he will offer you N's Zorua.. Of course you will need a blank space in your team to accept it.. Now you will be able to challenge the gym..

This time, the gym will be Ground-type.. The gym leader is called Clay, Pokes' lvl about 31~33.. So if you don't have Water or Grass-type Pokes.. I will have to say good luck to you then.. :D Anyway, this time, save your time, don't explore anywhere.. However, if you think you will be out-lvl.. Then you have no choice but to explore the west side of Driftveil City, Route 6.. There's tons of trainers here.. But you might not want to enter Chargestone Cave cause you won't go far, though there's 2 trainers you can still battle..

After you have beaten Clay, go to the south.. This place which is supposed to be blocked is now opened.. And now, you are in Pokemon World Tournament (PWT).. You will be asked to participate in a tournament.. It's a 3 vs 3 Pokes single battle.. There's no lvl restriction for you, but all your opponents will be using Lvl 25 Pokes.. The line up should be something like this..

It's pretty obvious who you will challenge here.. You will start by battling with your rival, then Cheren.. Lastly Colress.. Once you are done with this tournament.. You will notice a Team Plasma's member walking to the port in PWT.. Your rival will chase after him.. Of course, you will have to chase after your rival who had boarded their ship.. Inside the ship, you, Cheren and your rival will have to battle with Team Plasma.. First, you have to battle 2 grunts alone, then you have to tag battle with Cheren/your rival once each..

After you have beaten all them, all of you will be sent out of the ship.. Now you are done here, head back to PokeCenter.. Buy lots of healing items and maybe Escape Rope just in case.. Then to the west side, Route 6.. On the way, you will meet Cheren who will tell you about the temperature drop around Unova in the lab.. Here, you will also be able to receive a DW Deerling from one of the scientist.. While marching to Chargestone Cave, a Cobalion should appears and runs away shortly.. Now go through the cave.. There will also be a doctor half way through the cave.. Once you have passed this cave, you will  be at Mistralton City..

Relic Passage/Volcarona
On the leftmost side of PWT, you should notice there's someone standing near a cave.. You will need Strength HM to go through this cave.. This cave will leads you to Relic Castle which is supposed to be in the desert.. But if you went there, you should notice that you will not be able come here as the the structure of the Relic Castle has changed.. Anyway, it's pretty simple to reach Relic Castle from this cave.. Volcarona will be at lvl 35, truly under lvl-ed one..