France, in the near future. The Defaulters, humanlooking robots, spread terror among the few remaining communities, at war between one another. The young Till gets through by moving from one shelter to another with his temporary companions on the Surface, where survival is harsh.

As for twins Orion and Hestia, they live in the high-tech underworld web of cities, hoping to see the sun again one day. Hestia is brilliant with technology and helps the smooth running of society, while Orion wants nothing more than to join the militia and get the opportunity to go back to the Surface.

They are far from suspecting what is coming for them. The meeting between Orion and Till will shatter their certainties. The worst enemy is not necessarily the one you believe to be.