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To start this chapter, you will need to bring back HM Surf from Solar Cave, and have bought the Friend Area Southern Island. (It is the most expensive area, costing 9,500 Poké.) After doing both, you are awakened very early in the morning. You walk outside, just in time to witness something fly by at high speeds. Hours later, you partner takes you to Pokémon Square. The younger Kecleon is furious, because all of his TMs have been stolen. Alakazam traces the thief to the Northern Range, and your team is ready to track it down.
The dungeon is 25 floors. All Pokémon found there, except for Spinarak and Seviper, are part Flying, so Electric, Rock, and Ice types will dominate.
Waiting on the 25th floor is the culprit, a Latios.
After defeating Latios, you reappear in Pokémon Square. Latios stole the TMs to try and rescue his sister, Latias. She fell into an inescapable dungeon after being hit with a small meteorite. Because of the Teleport Gem, your team is up to the rescue.
This dungeon is 25 floors and, like Northern Range, has a Flying-type theme.
On the 25th floor, Latias will be waiting for you. Teleport back to Pokémon Square to watch the two Eon Pokémon reunite. They have no money, so what's your reward? The two will join your rescue team.