17-year-old Jacob and his mother spend two years in space, defying both gravity and his rare autoimmune condition. After his innovative therapy on the spaceship turns successful, the boy is ready to go back home with new strength and improved mobility. But as they prepare to return, the Earth is no longer safe. A new world-wide danger threatens everything Jacob has thought for, and he has to make the toughest choice of his life. Will he risk everything to live like a normal teenager, or will he stay in the only place that keeps him safe?