Pokémon Grass Emerald is a grass-only run of Pokémon Emerald, known in Japan as Pocket Monsters Emerald (ポケットモンスター　エメラルド Poketto Monsutā Emerarudo,?), is a role-playing video game developed by Game Freak and published by Nintendo for the Game Boy Advance handheld video game console. It was first released in Japan, and was later released in North America, Australia, and Europe. It is an enhanced remake of Pokémon Ruby and Sapphire.

Players control a Pokémon trainer, whose general goal is to traverse the Hoenn region and conquer a series of eight Pokémon gyms in order to challenge the Elite Four and its champion. Players capture creatures called Pokémon along the way using Poké Balls and use them to fight other trainers' Pokémon. It keeps Pokémon that debuted in Ruby and Sapphire while incorporating Pokémon from Pokémon Gold and Silver in the after-game, that were not featured in Ruby and Sapphire. It features the same plot of Ruby and Sapphire except it incorporates the Pokémon Rayquaza into the story and introduces the Battle Frontier, a tournament in which players' characters can participate after the game's credits.

The setting and plot remains largely the same as Pokémon Ruby and Sapphire. Players can choose from either a boy or girl (both of whom have been given new green costumes) and choose between one of three Pokémon before they proceed into the rest of the game's world. Players are tasked with filling a device called a Pokédex by catching different Pokémon species and evolving them. They are also tasked to complete eight gym challenges and defeat the Elite Four and its champion by battling their Pokémon. Along their journey they face both Team Magma and Team Aqua (whereas Ruby and Sapphire had you face only one of them based on which version you had). Each has a goal to change the world to their liking; Magma desires more landmass while Aqua desires more water. They plan to accomplish their respective goals by summoning the legendary Pokémon Groudon and Kyogre. Late in the game, they both summon their respective legendary Pokémon; however the Pokémon refuse to obey either team and begin fighting, which puts the world in a constantly switching state of droughts and rain. The players' character climbs a tower in order to summon the legendary Pokémon Rayquaza, who quells the other two Pokémon's rage. After players beat the Elite Four, they are able to encounter two Pokémon flying across Hoenn called Latias and Latios and can access an area called the Battle Frontier. less