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All right! You've beaten the Grass Club! But before we go onto the next Club, we have some... "errands" to run:
This is really just... sightseeing, but the Challenge Hall will come up later. Everybody's waiting for the Challenge Cup!* But that'll come later. Outside! Now! Let's go to the Mason Laboratory!
Go to the room at the right. Select the computer over the bottem-right computer. Insert the Grass Medal, and that will start the Grass Medal Auto Deck Machine will start. The decks that can be made (but only if you have the right cards) are: Insect Collection Deck, Jungle Deck, Flower Garden Deck, Kaleidoscope Deck, and Flower Garden Deck. When you're done there, head outside.
This is optional, but anyway, at the Pokémon Dome, if you look at the "Plate of Legends," when you're done reading, Ronald will enter and claim that he has one more Medal than you. If you check the doors, a Mysterious Voice will tell you to "Leave this place!" Well, let's.
So, to the Science Club! It's north of the Grass Club. In the lobby, there's a Lad who talks about Ishihara, who lives (SHOCKER!) in Ishihara's house. Now he will appear there. Uh... Sorry, but—
Ishihara says that he will trade Pokémon cards with you sometime and that his books may be helpful. On that note- Bye!
Science Club (again)
This Club uses Grass-types, so again, use Fire-types. Time to go to the main room, in the north. Duel* that guy that you see when you enter the room. His name's Erik, and he's a Club Member. He uses the Poison Deck, which only has type Pokémon in it. The prize for winning is 2 Evolution Booster packs. In the PC in the lobby, there should be a "Mail 3" from Dr. Mason, sending a booster pack. Close to the northeast corner is David. He uses the Lovely Nidoran Deck, which mostly uses types, but also has 6 types. Win, and you will earn 2 Mystery booster packs. Now, duel that guy standing in the way of the man at the desk. He says that the Club Master,Rick, is busy and that to duel him, you have to duel this guy, Joseph. He uses the Flyin' Pokémon Deck. It mostly has types, but also has 7 types and 2 types. With this deck, Fire-types have no advantage unless you use a Porygon's Conversion 1, but never mind anyway. The prize for winning is 2 Laboratory booster packs, and of course Joseph stepping aside. Now save and challenge Rick!