Requirements: You must be Kanto and Johto Champion.
To start the Harry Potter Quest, go to the train station in Saffron.
To get access to the railway station you need to do two requirements first:
1.) Get a ticket: Search in Saffron for a house with a different coloured rooftop. The Copy cat wants a Pokedoll, which you get from the Pokemon fanclub in Vermilion. Bring her the doll to get the ticket.
2.) Go to the Powerplant and defeat the burglars (quest). To get this quest, go talk to Hank, who asks you to scare away the burglars. After completing this quest, the railwaystation has power again.
Now you get entry to the station.
If you can enter the station, look for the entrance to platform 9 3/4 on the top wall.
To start the quest you have to talk to Ghosty Gertrude, then Meg appears on the platform. Talk to her and the quest will start.
Now you need to gather clues about Harry’s whereabouts.
Five are needed to fulfil the quest.
1.) The first clue is located at the platform 9 3/4 right at the entrance on a table.
2.) Clue number 2 is located in the Ecruteak City in the theater.
3.) Clue 3 and 4 can be found in the Ecruteak graveyard. You have to enter a cave, then use the third-last and fourth-last ladders to reach the clues.
4) The last clue is also located in the Ecruteak Graveyard, Go up the ladder by the fourth clue, which I have marked with arrows, and walk past the NPCs and the fifth ladder is hidden as a gravestone which is also marked.
Now that you have gathered the clues, go back to Meg; talk to the Ghosty Gertrude on the second platform again to make Meg appear, then go to Meg on the first platform. Now Harry has appeared, Go talk to him, Ron will join his friend, and this will trigger a triple-battle versus them.
Congratulations, after successfully beating them, you have now finished the Harry Potter Quest !!!