After School!

Airi is an average 12-year-old girl. She goes to school, hangs out with her friends, and loves being outdoors. The thing is, she can only be outside for 30 minutes a day. Welcome to Airi's life. A catastrophic nuclear war reduced the world to a radioactive wasteland and forced her and other humans to live deep underground. But, this doesn't bring Airi or her friends down. As they explore above ground, they make shocking discoveries not taught in school.

Manga Planet has the first two chapters for free on the official website. It also has the latest chapter up for free for two weeks.