Earth drifts into space. Governments rush to develop fusion reactors, to colonize mars, to construct domes that will retain enough heat to sustain life. When everything fails, they dig toward Earth's core. A city is built seven miles beneath Kansas. All but 300,000 souls on Earth perish. 135 years in the future, their civilization thrives. Central City is a bustling metropolis with shops and factories, entertainment and religion. The subterraneans live their lives mostly unaware that the magma is cooling faster than expected. Life in the known universe grows perilously closer to extinction the further they drift from the sun. Melody Jones, a genius high school student, is frustrated with the limitations of life in a small town tucked away in the outskirts of the cave seven miles below the surface of Earth. While obtaining her doctorate at 'College', Melody is one of only a few who see the looming disaster, and she alone dares to propose a solution. She wants to lead a surface expedition to track down the source of trace sulfur gases. If she can find a massive cluster of erupting volcanoes and contain that heat in a dome, they can test a new technology to bring the power of the sun with them no matter how far they drift in space. But time is running out. When the air freezes solid, all hope will be lost. With the help of a childhood friend, Bobby Monk, who has been in love with her all his life, she raises the funds, helps invent the technology and puts together an athletic and skilled team that heads out on the expedition. Her team soon finds that the surface is lifeless but animated and deadly. Humanity's last chance to avoid extinction plummets with each fallen explorer ...