Two legendary pokemon, Solaris and Lunarox, give birth one night. an egg falls to the ground and immediately hatches. Over 100 new Pokémon spring out and take to the air, land and seas. Their duty done, Solaris and Lunarox fly off to the sun and moon, respectively.
One day, after deciding your gender, your name, (default is Ralph for boys and Betty for girls) and your rival's name, (Boy if you're a girl and vice versa, same default name) you wake up in bed and change out of your PJs. You go downstairs. Your mom tells you that Prof. Oak is looking for you. Once you cross a more advanced Pallet Town to get to his lab, Oak tells you that he has made a new Pokédex and that you and your rival are expected to fill it. He gives you a choice of 3 starter Pokémon (grass, fire, water) and sends you off on your journey.