((earth is threatened by the invasion of alien monsters with each of them have different abilities. normal firepower doesn't affect them, but from years of struggles humanity regain their hope in the form of giant humanoid mechs called Units created by 'Humanity Defense Force' where your father is the commander. he left you with your uncle when you were 4, and now called you to his workplace to recruit you as a pilot. the force's captain, Erin will pick you up at the station))

you're looking through the file guides you got from the mail sent by your father, when suddenly a monster attack the city. a car quickly drift up in front of you

the door opens

Erin: you're the commander's kid, right? get in! we gotta go quick to the base!