From the introduction:
Whether it be the Xavier Institute For The Gifted, PS238, Whateley Academy, HIVE, or the S.H.I.E.L.D. Academy, many if not most universes that contain costumed heroes also contain a school where teenage metahumans are trained and educated.
Now you are going to attend one of these schools. Maybe you are being trained to be a hero, maybe a villain, maybe a covert government agent, maybe you are even being taught to live a normal and happy life. No matter what the school is teaching you however you are stuck here until you graduate, or ten years pass. Whichever comes first, though you can stay past ten years in order to graduate, if you choose to do so.