The area is filled with patches of long grass, which prevent using both bikes and hide Trainers and wild Pokémon. One of these wild Pokémon is Tropius, which can learn Fly along with four other HM moves. It will be very useful if you cannot or do not want to teach those HM moves to the Pokémon that you use in battle.
A handful of Trainers in the southernmost patch of long grass like to copy the movements of any Trainer passing by, collectively earning them the "Mimic Circle" nickname. They move when you do, so outmaneuver them to pin them down and start battling. Each one remains in a certain area, which gives you a chance to corner them.
Feebas can only be found by fishing in one of six water tiles along the route. Adding to the difficulty, other Pokémon besides Feebas can also appear in the Feebas tiles as well. There is no known easy method to determine which tiles contain Feebas: the only way is to fish repeatedly in each and every water tile on the route, doing so enough times to be reasonably confident that no Feebas are in that tile (or else risk missing a tile). (If the player reels in one Pokémon in every tile, there is a 1 in 64 (approximately 1.6%) chance that the player will pass over all six Feebas tiles without reeling in a single Feebas.) Any rod can find Feebas, and Feebas can be fished from the same tile many times. The tiles' locations are independent of the trend in Dewford Town, although the tiles' location will change every time the trend does.
Located on the north end of the route, the Weather Institute is a high-tech facility used to study and research the intricacies of weather patterns across Hoenn. This research seems to have attracted the attention of Team Aqua, as several Grunts have been stationed outside.
Visit the back room to find some Team Aqua Grunts searching the place. Before battling them, head to the northwest room to find a comfy bed and rest your Pokémon before continuing on. There is also a PC here in case you should need to reorganize your team.
Looking for Answers
When you reach the second floor, you find the source of the disturbance: Aqua Admin Shelly is harassing the researchers! She is here looking for information about extreme weather conditions, and to steal one of the Institute's Castform, a rare species of Pokémon. She can't allow you to meddle in the team's plans, and draws you into battle.
The Admin simply shrugs off her defeat, claiming that the team has other plans before she and the Grunts leave the building. As thanks for your help, one of the researchers even rewards you with a new Pokémon, Castform, which changes its type and appearance based on the current weather.
Rival Battle 4
Leave the building and cross the upper bridge. May/Brendan catches up to you when you reach the nearest stairway. Your friend wants to see how much stronger you've become, and wastes no time challenging you to a battle!
Once you defeat her/him, your friend rewards you with HM02 (Fly). It's a strong move in battle and even more useful when used in the field, though you'll need to win the Gym Badge from the next city first. She/He then runs off, leaving you to continue on to Fortree City.
Just as your neighbor climbs the hill to Fortree, Scott is headed south away from it. He congratulates you on winning your latest match, and expects great things from you at the Fortree Gym.
Fortree City is located in an old-growth forest with many towering trees. These ancient arbors are so large that the residents were able to build cozy homes among their branches. A shop offering Secret Base decorations can be found in the southeast part of town, and the Fortree Gym can be found in the heart of the city. Unfortunately, the Gym's entrance is obstructed by something invisible.
Climb the ladder near the Poké Mart and head east across the rope bridge to reach a shop with a selection of Secret Base decorations for sale. Desks can be purchased at the counter to the left, while chairs can be purchased at the counter to the right.
Speak to the Pokémon Breeder in the northeast house to see his Wingull fly off on an errand. Return later to see if it's successful!
Reveal Your Hidden Power
The north-northwest house belongs to an old woman. Speak to her to take a quiz. She holds a coin in her hand, and asks in which one you think it's hidden. Guess correctly three times in a row to receive TM10 (Hidden Power)! This unique attack is listed as a Normal-type move, but its type and power vary depending on the Pokémon using it.
Speak to the woman's elderly husband to learn that he talks in his sleep. He offers to teach the move Sleep Talk to a Pokémon, one time only.
Time for a Trade
The little girl in the northwest house wants a Volbeat. If you happened to catch one back on Route 117, she'll give you her Plusle in return. Plusle arrives holding a Wood Mail.