In the beginning of the movie a soldier with orders to kill these hidden, sleeping children adopts one who is later on able to end a war between one faction (the one the soldier is from) that lives in a massive robot, and one that was forced to live outside it. The girl is also able to control the robot. Please help, it has been driving me crazy.
It’s probably wrong but I’m gonna suggest “Metropolis” from 2001.
https://en.wikipedia.org/wiki/Metropolis_%282001_film%29