The show takes place in the future where the the Holy Britannian Empire has taken over most of the world. Lelouch Lamperouge is a Britannian high school student in the Britannian conquered territory known as Area-11, formerly known as Japan. One day he gets caught in the crossfire of a skirmish between Britannian forces and a local resistance group. He sees the harm his country causes and gets the power that he feels will help him make the world a better place.
https://youtu.be/DR1d_Pm729o
