Lyric discussion by scrumtralescent 

Cover art for I'm Alive lyrics by Blind Guardian

It may be about the Death Gate cycle, but I don't think so due to the references to 'level 99' and just doesn't quite seem to fit.

I think it's about a book called This Time Of Darkness by HM Hoover. It's about an eleven year old girl who lives on the ninth level of an underground city governed by your typical dystopian Big Brother-like government, supposedly the only habitable location after some sort of apocalypse that happened hundreds of years ago. She's learned to read, which is something discouraged by the government, who instead use pictures and animated signs('magic runes'). Because she can read, she's watched more closely than others.

They are told every level of the city is identical, but she meets a boy who claims to be from 'outside', which he describes as sunny, habitable, and otherwise pretty damn nice. She begins dreaming and thinking about it all of the time('dream forever, sunlight instead of neon light'). They decide to attempt to escape, first to level 80, then level 99. The book describes what they find, their attempts to avoid capture, finding better conditions as they go up, discovering the government's terrible secret, etc.