POKEMON RUBY AND SAPPHIRE

Pokémon Ruby and Pokémon Sapphire, released in Japan as Pocket Monsters Ruby and Pocket Monsters Sapphire (ポケットモンスター ルビー・サファイア, Poketto Monsutā Rubī, Safaia?), released on March 17, 2003 in North America for the Game Boy Advance, mark the beginning of the third generation in the Pokémon series of RPGs. Ruby and Sapphire were succeeded in 2004 by Pokémon FireRed and LeafGreen and in 2005 by an enhanced remake titled Pokémon Emerald. The games feature 386 species of Pokémon.

Setting and plot
In the Ruby and Sapphire Pokémon games, the protagonist moves to Littleroot Town of the Hoenn region from Johto. Upon rescuing Professor Birch from a wild Poochyena, the player receives the starter Pokémon he/she used to save the professor (Treecko, Mudkip or Torchic), and begins his or her journey. Like the previous games, the player's goal is to collect eight Gym Leader badges so he or she can challenge the Elite Four and become the Pokémon Champion. In these two games, the rival is of the opposite gender and is more of a friendly helper, checking the player's progress at various times and giving items to help the player advance through the game.
In another difference from its predecessors, the protagonist's father, Norman, is the Petalburg City Gym Leader. When the player enters the city, he or she meets Norman. Shortly afterwards, a young boy named Wally enters, who wants to catch his first Pokémon before he has to move away from Petalburg. The player accompanies him out into wild grass, where he catches his first Ralts. Wally is overjoyed and thanks the player. Later on, the player faces him again in Mauville City, where he is seeking to challenge the Gym Leader there. After the player defeats him, he reconsiders and decides to improve his team.
The main antagonists that the player faces are Team Magma and Team Aqua. The two teams coexist in both games, one team being the villain and the other being good. In Ruby, Team Magma plans to deplete the sea and create more land by awakening the ancient Pokémon Groudon. In Sapphire, Team Aqua seeks to expand the ocean by awakening the ancient Pokémon Kyogre. Through a series of confrontations, the protagonist learns of their agenda and attempts to stop them. In the end, Magma or Aqua managed to awaken the ancient Pokémon. However, once they awaken it, it does not obey their orders. Instead, Groudon brings eternal, withering sunshine to Hoenn, while Kyogre brings eternal rain. The player must enter a location called the Cave of Origin, where Groudon or Kyogre resides, and capture or defeat it. Once done, Hoenn returns to normal.
After the player acquires the eight badges, he or she enters Victory Road, a location with high-leveled Pokémon and trainers. The Pokémon League and the Elite Four are stationed in an area north of Victory Road. Near the end of the area, Wally catches up to the player and demands another battle. His team is much improved, and after the player defeats him he vows to retrain until he triumphs. After beating the Elite Four, the player can battle him again.
Once the player defeats the Elite Four, they will be transported back home. Once they go downstairs, Norman will be sitting with the player's mom and Norman walks over to give the player the S.S. Ticket, which is needed to use the ferry at Slateport and Lilycove City. After that, there will be a news report saying there is a colored Pokémon at flight (Latios in Ruby and Latias in Sapphire). These Pokémon are available to catch.
Also, after beating the Elite Four, the player can access a place called Battle Tower.
At the Battle Tower you will find many new national pokemon to capture such as Sudowoodo or Smeargle etc.

Differences from previous games
Ruby and Sapphire feature a number of distinct differences from the original set of games.
Because of numerous changes in the battling system, these two games are not compatible with the first or second generation. New battling mechanics include Abilities and Natures. Abilities add certain characteristics that add strategy to battling. Natures raise and lower two stats (Attack, Defense, Sp. Attack, Sp. Defense, and Speed). Another new mechanic is 2-on-2 battles, where the Pokémon trainers send out two Pokémon at once. There are also more hold items than there were in the first two games. The berries have also been renamed. The new names are similar to names of actual fruit, instead of being names which symbolised what each berry did.
These two games also have Pokémon Contests and Pokéblocks. Pokémon Contests are most like beauty contests, where Pokémon do moves and perform before a judge. Pokéblocks are synthesized from berries, which the player plants, waters and picks. The player uses a tool called a Berry Blender to make Pokéblocks. Each Pokémon can eat up to 12 blocks, and each block enhances a characteristic (Cool, Cute, Smart, Beauty and Tough). Some Pokéblocks increase two stats, but halve the amount each stat gets. Feebas is the only Pokémon that is affected by these stats outside of Contests; it will evolve into Milotic after achieving a maximum Beauty stat.

credit: Wikipedia