Request #400 From sagelazenby

I read a book in 5th grade where there was a society told they were living in a massive high-rise structure to escape the radiation of the world below. The perception was shattered when a boy from outside found his way in, revealing the structure is actually underground, and the radiation risk has diminished, although that information is kept from society. The plot follows the boy and a girl who make their way up the structure to the surface. The cover had the two children running toward the viewer in a tunnel. The year was 1995, and the cover art looked like it was straight out of the ’70s