(Because why not?)
One day you suddenly find yourself in the body of Ash Ketchum the day he's getting his first Pokémon. You quickly realize as the protagonist you have to stop the big bad world ending events (Jirachi wishmaker, Jewel of life) otherwise the consequences of the destruction caused would affect you greatly. Eventually snowballing into the Pokémon world become an apocalyptic death world impossible to live in:
>Every single movie and episode is going to happen in a timeline.
>You can capture or trade any Pokémon you want (e.g: Trade away Butterfree, keep Togepi egg).
>While it would be possible to capture the legendaries. They all have to attend to their natural duties and would only have the time to help you during movie events.
>Movie events and anime plotline colliding create a consistent Pokémon world so if Darkrai and Latias are killed, Tobias can't use them.
>It's not necessary to attend the Pokémon league, fight gym leaders or attend contests. Any career path is open to you
>If you do evil acts (e.g: Tie Misty while she's fishing and rape her) then it will have consequences like serious police investigation and legendaries sensing the evil in your heart.
>Pikachu can change depending on your actions, it could become a mighty Raichu or leave you to stay with the Pikachu herd.
With these conditions in mind you set off into the Pokémon world to grasp the limited opportunities.
Who would you capture, what career would you choose, who would you try to romance, how would you handle the villains, who would you befriend or not interact with and most importantly how would you survive? Be creative and have fun.