Beneath a Sunless Sky by Jessica Alter

Ten years after child prodigy Remy had an accident which robbed her of a prestigious future, she walks the edge between life on Solaray-lit Level One and the gloom of the UnderDome, waiting for an opportunity to return to her place among the elite ruling class and put the nightmare of living as a sub-human behind her. In the first book of the Dome Trilogy, Remy’s life spirals from her control; she is condemned to live her life in the most reviled pit in the Dome world, known to be populated by brutish beasts too inhuman to even live on the edge of society. When she arrives, however, she discovers that humanity does not belong only to the citizen, life on Level One is not what she had believed it to be, and a threat more grave than the UnderDome, itself, lurks just beyond its shadows.