In a future where humanity huddles in decaying domed cities controlled by alien invaders, Rhoswen and her best friend Anna work as make-shift nurses in a tiny clinic run by the young doctor Terrian. The city is ruled by the aliens' violent, half-breed offspring who serve as brutal overseers. Rhoswen and Anna have always tried to avoid these overseers at all cost, but their lives change when one of those same terrifying offspring is brought into the clinic, injured and unconscious.