Trò chơi Pocket Monsters : Ao

After venturing alone into tall grass, a voice warns the player to stop, which is revealed to be Professor Oak, a famous Pokémon researcher. Professor Oak explains to the player that wild Pokémon may be living there, and encountering them alone can be very dangerous. He takes the player to his laboratory where the player meets Oak's grandson, a rival aspiring Pokémon Trainer. The player and the rival are both instructed to select a starter Pokémon for their travels out of Bulbasaur, Squirtle, and Charmander. Oak's Grandson will always choose the Pokémon which is stronger against the player's starting Pokémon. He will then challenge the player to a Pokémon battle with their newly obtained Pokémon, and will continue to battle the player at certain points throughout the games.