After leaving the ferry and explaining a bit about the island, Bill introduces the player to Celio, a programmer who runs the Pokémon Network Center. This building acts as a traditional Pokémon Center, and also houses the Pokémon Network Machine, which is currently undergoing maintenance. After connecting to Kanto's PC storage system, it will then be able to connect to the storage systems in Hoenn and Orre, which would allow the player to trade with residents of the faraway regions. Until the work is complete, the normal PC services will be unavailable.
While Bill and Celio get to work on the machine, Bill asks the player island is run by a man with an interest in gemstones, and Bill asks the player to deliver a Meteorite to him. To help with the task, Celio hands over a Tri-Pass, a ferry ticket that allows travel between the three northernmost islands in the archipelago. He also gives the player a second page for the Town Map which details the different areas of One, Two, and Three Islands.
South of the wharf is a small islet, with only a single Trainer swimming nearby. This is Treasure Beach, known for the valuable items that regularly wash up on the shore. The tides usually replace these items by the next day, allowing treasure hunters to easily stockpile these rare items.
Kindle Road, on the island's rocky eastern side, leads northward from the town to Mt. Ember. The grassy western path is packed with Trainers, and is the only location where wild Ponyta and Rapidash can be found. The northern edge of the main island is home to the Ember Spa.
Mt. Ember Summit
Ember Spa is a small hot spring where people and Pokémon can relax and restore their health. The old man standing between the two waterfalls claims to have hewed the cave out of a gigantic boulder many years ago. No longer needing his tool, he hands HM06 (Rock Smash) over to the player.
Immediately inside the entrance, a Hiker will offer to teach Explosion to one of the player's Pokémon.
To the east, a pair of Rocket Grunts are muttering about digging and treasure. To the west, the trail zigzags its way up the side of the mountain. Go east from the jogging Crush Girl to get a Dire Hit, then head north from Pokémon Ranger Logan to enter the mountain's interior.
Follow the tunnels eastward through the volcano to re-emerge on a higher level of the mountainside.
Climb the first stairway to find a group of boulders to the east; a Fire Stone sits on the ledge beyond. The western stairway leads to a hidden Fire Stone and an Ultra Ball.
A second group of boulders litters the summit, and the mountain's resident legendary Pokémon—Moltres, the third of the legendary birds—is roosting beyond that. There is only one, so save the game before starting the battle.
Fly back to the Pokémon Network Center, and take the ferry to the next island.
Two Island, the second island
Two Island is a small island with little more than a Pokémon Center. The Joyful Game Corner is located here, and the Market Stall offers different items over time. Unlike in the town of One Island, the waters around the wharf are too rough, so it is impossible to surf or fish in the town itself.
The owner of the Market Stall moved here from Celadon City, and set up shop with his younger brother. Only Great Balls and Fresh Water can be purchased initially, but his selection changes after certain events have taken place.
Cape Brink is a short mountain road on the island's north side. The lone house belongs to a Channeler who has perfected three ultimate moves of their respective types. She offers to teach Frenzy Plant to Venusaur, Blast Burn to Charizard, and Hydro Cannon to Blastoise. These attacks are elemental variations of Hyper Beam, and may only be taught once each, and only to the player's original starter Pokémon.
The house to the south of the Market Stall belongs to the Move Maniac. He claims to know every single move a Pokémon can learn as it grows up. He also happens to be a mushroom maniac. For the small price of either two TinyMushrooms or one Big Mushroom per transaction, he can re-teach a forgotten move to one of the player's Pokémon.
Joyful Game Corner
The Joyful Game Corner is located next door to the Move Maniac. Unlike the Game Corner in Celadon, this one features two mini-games where Pokémon compete against each other. But these games will have to wait, as the owner is missing his daughter, Lostelle, who has not shown up yet with his lunch today. He pleads with the player to search Three Island. Suddenly, a Biker rolls in, mistaking the area for Three Island. The owner chases him out, and asks the player again to save Lostelle.
Three Island, the third island
Three Island consists of two plots of land; a larger island to the east that holds the town of Three Island, and a smaller forested islet to the west. Upon leaving the wharf, the player finds a gang of rowdy Bikers, the Kanto Rider Federation, harassing the residents. Fight them off, and they reluctantly leave the island in peace.
Three Isle Port is located on the south side of the island, connecting the wharf to the town of Three Island. A small cave leads into the rock face to the east.
Three Isle Path
Three Isle Path is a small cave on the south side of the island. The cave is known for its supply of gold, which has attracted one of the residents. By the time the player has defeated the Elite Four and received the National Pokédex, the cave will have expanded into a tunnel. The man was evidently successful in his search, as he shares a spare Nugget with the player. This tunnel leads to an isolated cliff with a single patch of tall grass, inhabited only by Dunsparce, which cannot be found anywhere else in the wild.
As soon as the player arrives here, Bill and Celio have already managed to link the Sevii PC system with that of Kanto, restoring all normal PC functions in the process.
The southwest house, with the red roof, belongs to Lostelle and her father. She is not here either, so she must be farther along the island. With the Bikers gone, one of the residents informs the player that she headed off toward Bond Bridge a while ago.
Bond Bridge links the town on the eastern island with the Berry Forest on the western islet. Several Trainers can be found here, and valuable items sometimes wash up near the bridge.
Berry Forest is a dense, dark forest, and is well known for its constant supply of Berries. Lostelle can be found in the northwest corner, terrified by a wild Hypno. Defeat or capture it, and she gives the player an Iapapa Berry as thanks.
With Lostelle safe and sound, her father can return to running the Game Corner. The two multiplayer mini-games offered here are Pokémon Jump, where the player's Pokémon must jump a Venusaur's Vine Whip in sync with others to earn points within a time limit, and Dodrio Berry Picking, where several Dodrio line up and try to catch as many Berries as possible before time runs out. The first is restricted to small Pokémon that can jump, while the second requires each entrant to have their own Dodrio. These games may be played with other FireRed, LeafGreen, and Emerald players.
Bill and Celio have finished their maintenance work by now. Bill and the player return to Cinnabar Island, from which she can continue on to the final Gym.