The first thing to notice about Castelia City are all of the big buildings. This city is huge. After you first enter from the Skyarrow Bridge gate you can walk down to a pier. There is a scientist that will give you an elemental stone. You can use it to evolve the elemental monkey you received back in the Dreamyard if you want. Return to the main road and then walk left until you find the Pokemon Center.
Inside the Pokemon Center there will be someone in line at the healing station. Talk to her and she will ask you to walk upstairs to the globe and select where you live in the world. This is used when you battle other people online.
Before we walk up any of the roads to go into inner Castelia City, walk left from the Pokemon Center to find different buildings to explore. The first building you can enter has brown and green doors. This is the Battle Company. When you walk inside, a man with gray hair will talk to you before talking the elevator up. Enter the elevator and go to floor 47. Up here are a bunch of people waiting to battle. The closest girl is a Clerk.
If you talk to the man to the right of the Clerk, he will give you three Quick Balls and three Timer Balls. Quick Balls are four times stronger than a regular Poke Ball if they are used on the first turn of battle. After the first turn, they are just as strong as a Poke Ball. In contrast, Timer Balls get stronger after each turn of a battle. There is a Clerk to the left.
To the right is a scientist that will give you a Scope Lens, which gives the holder a better chance of getting critical hits. Head back to the elevator and go to floor 55. Walk down to find a Hyper Potion. Hyper Potions heal 200 HP, which is probably too powerful for any of your Pokemon right now so you may want to save it. To the left is a Clerk.
He will give you Exp. Share. If a Pokemon holds Exp. Share it will get experience from any battle, even if it didn't get sent out. It's a great item when you catch a new Pokemon that is a low level. That's all there is to do at the Battle Company, so head down the elevator and back outside.
The building to the left of the Battle Company is the Passerby Analytics HQ. Talk to the scientist and he will appoint you as a statistician. This means you can answer questionnaires and get information from other people while your C-Gear is in PasserBy mode. If you talk to the blonde-haired woman in the northwest corner of the building she will ask you to answer some questionnaires. She will add the questionnaire to your Survey Radar after each one you complete. If you take all 9 questionnaires she will give you a Soda Pop. The Passerby Analytics HQ is the last building on this road that you can enter, so now it's time to start traveling up the different streets. Walk up the west-most street towards the Pokemon Gym.
The entrance on the right side of this street is the Castelia Gym. Cheren pops out as you try to enter. Once he leaves, Burgh comes out and says Team Plasma is in Castelia before leaving for the piers. You can find them at the middle of the five piers back by the Battle Company. Before going there you should finish exploring Castelia for more items and battles.
The building on the left side of this street is empty for now, so you can skip it and keep walking up. Now you are in the Central Plaza of the city. There is a Dancer who wants to battle by the fountain.
Once he is defeated, he will challenge you to find two other Dancers and defeat them to win a prize. North of the fountain is a set of vending machines where you can buy drinks that heal HP. Walk down the middle-left of the four streets, Narrow Street. This is a very narrow alley with two old men who don't want to be disturbed. Further down you can find the second Dancer by the sewer hole.
Walk down further to find a cafe. If you talk to the manager inside, she will give you a free Lemonade which restores 80 HP. Back in the alley, if you walk down even more there will be a sound coming from one of the dumpsters. This may seem like a battle, but the guy in the suit actually gives you TM 70, Flash. In-battle, Flash will lower your opponent's accuracy. In-field, Flash will light up dark caves. Make your way back to the main road or the Central Plaza and enter the middle-right street, Mode Street.
This area is hustling and bustling. There are plenty of business people running about. Don't worry about running into any of them because they will dodge you. On the right side of this street is an art gallery with a Harlequin inside. He will ask you to show him a certain type of Pokemon each day. If you show him the correct type of Pokemon, you will get a berry as a reward. The type of Pokemon and berry is different every day. That's all there is to do on this street, so make your way to the right-most street, Castelia Street.
There are a lot of people walking on this street too. The building on the right of this road has a special event. If you bring an event Celebi transferred from Generation 4 using the Relocator to the lady on the first floor, the person on the left will show its true form. It is actually a Zorua that will join your party. Even if you don't have a Celebi, she will still show you Zorua to fill in your Pokedex, which will help you out later. Upstairs in this building is where the Game Freak crew reside. Game Freak, the creators of Pokemon, always put a Game Freak headquarters in each game. Usually there is a cool unlockable at a certain point in each game so you may end up making your way back here.
Head back outside and enter the building on the left side of the street. There is a woman who will give one of your Pokemon a massage once a day which will increase their happiness. Some Pokemon only evolve through happiness, so this is a good place to keep in mind. Upstairs is a hiker that gives TM 44, Rest. Rest puts a Pokemon to sleep and replenishes all of his or her health.
Make your way to the fountain in the Central Plaza and keep walking north to enter the street that leads to Route 4. On this street there are three entrances. Go into the building on the left. Here you can find the Name Rater. If you want to give any of your Pokemon a new nickname he is the guy that can do it. Upstairs is a scientist that wants you to tell him a phrase in order to unlock the machine he created. The phrase is:
This unlocks the Relocator, which can be accessed from the main menu. It allows you to transfer event Pokemon from Generation 4 games such as Celebi and the three shiny beasts which can unlock special events in Black and White. These event Pokemon were given away at GameStop and over WiFi in 2010.
Back outside, walk across the street and enter the southern entrance of the building on the right. There is a guy in a suit and sunglasses blocking the elevator. Answer yes to his question and he will let you to use the elevator. Go to the 47th floor. There is a party going on in this room and there are people from all over the world. If you talk to the little girl with pigtails, she will give you TM 45, Attract. This move can be used against Pokemon of the opposite gender to cause infatuation. An infatuated Pokemon will not attack half of the time because it is in love. Go back outside and use the second entrance of this building.
There is a scientist by the TV that will give you the Eviolite if you have seen over 25 Pokemon. The Eviolite will increase Defense and Special Defense by 50% if the Pokemon holding can still evolve. There isn't anything of note usdtairs in this building, so you have explored all of Castelia City other than the piers. Head back to the southern-most part of Castelia City and go to the pier in between the Passerby Analytics HQ and the Battle Company, Unity Pier. There you will find the final Dancer.
Once defeated, he will go back to the city fountain. If you have beaten all three Dancers, go to the fountain and talk to the middle Dancer to get an Amulet Coin. It will double the money you receive after a battle if the Pokemon holding it participated. There is currently nothing to do at the left pier and the middle-right pier so head off to the middle pier, Prime Pier, to meet up with Burgh. Make sure you have already tried to enter the Castelia Gym, otherwise Burgh won't be at the pier. Once you enter the middle pier, Burgh, Bianca, and Iris will tell you Team Plasma stole Bianca's Munna. A Team Plasma member will show up before running away. Burgh will chase down the Team Plasma member and you need to follow him. Head west toward the gym. Across the street from the gym is Burgh staring down some Plasma grunts. As you walk up, the grunts will talk and you should answer yes to their question to start a battle.
Once the battle is over, all of the grunts will run inside. Bianca and Iris show up and talk briefly before Burgh high-tails it into the building. Bianca and Iris follow Burgh, which leaves you no choice but to follow as well. After a lot of talking, a Munna runs away from Team Plasma into Bianca's arms. Team Plasma vanishes and Iris gives you a Yache Berry, which makes super-effective Ice moves do half damage to the holder. Once everyone leaves, you can pick up the stray Smoke Ball that Team Plasma left behind. A Smoke Ball allows you to run away from a wild Pokemon without fail as long as your active Pokemon is holding it. Now that Team Plasma is out of Castelia City, Burgh is free to battle you in the gym across the street.
Items in Castelia City:
Received from the man on the right-most pier if the first option is chosen.
Received from the man on the right-most pier if the second option is chosen.
Received from the man on the right-most pier if the third option is chosen.
TM 44 (Rest)
Received from a Hiker on the 11th floor in the east building of the right-most street.
Received from the cafe manager.
TM 70 (Flash)
Received from the man behind the dumpster near the cafe.
Three are received from the Clerk on the 47th floor of the Battle Company.
Three are received from the Clerk on the 47th floor of the Battle Company.
Bottom-left corner of the Battle Company's 47th floor.
Received from a Scientist in the bottom-right corner of the Battle Company's 47th floor.
On the 55th floor of the Battle Company.
Received from the Garbage Man on Battle Company's 55th floor after defeat.
Rewarded after completing all questionnaires at the Passerby Analytics HQ.
Received from the Dancer at the fountain after defeating all three Dancers.
Received from a Scientist in the building with two entrances in the northern part of Castelia.
TM 45 (Attract)
Received from a girl at the international party.
Received from Iris after defeating Team Plasma.
Left behind by Team Plasma.
Received from the Harlequin in the art gallery after showing him a Pokemon of the correct type and choosing the first option.
Received from the Harlequin in the art gallery after showing him a Pokemon of the correct type and choosing the second option.
Received from the Harlequin in the art gallery after showing him a Pokemon of the correct type and choosing the third option.
Received from the Harlequin in the art gallery after showing him a Pokemon of the correct type and choosing the fourth option.
Received from the Harlequin in the art gallery after showing him a Pokemon of the correct type and choosing the fifth option.
Received from the man in the suit in the Pokemon Center after you have traded 5 Pokemon.
Received from the man in the suit in the Pokemon Center after you have traded 10 Pokemon.
Received from the man in the suit in the Pokemon Center after you have traded 20 Pokemon.
Received from the man in the suit in the Pokemon Center after you have traded 30 Pokemon.
Received from the man in the suit in the Pokemon Center after you have traded 40 Pokemon.
Received from the man in the suit in the Pokemon Center after you have traded 50 Pokemon.