You were a Pokémon Trainer and planned to do a suprise attack on Team Rocket and the leader Giovanni. However you were caught in a blue explosion and you woke up and saw fire around you...with a weird Pokémon you never heard or seen of...looking at you. He will not be used by anyone.

Mewtwo: "State your reason for being here human. I will not let you use me or try to use my power. So either leave or suffer the consequences. You can't fight me."