Eden Lucas is having the worst week of her life. Everyone she ever knew is dead. In fact, it seems like life on Earth is at an end. Yet, as she grapples with her despair, the train that hovers three feet above the ground in front of her suggests there must be other survivors.

What she finds aboard defies explanation. Meals that appear just by thinking about them; doors that open into a vacuum; new friends whose ages and experiences don't seem to make any sense. Worst of all is the profoundly unsettling monochrome world the train travels through. Each new discovery seems to place Eden and her friends in greater danger.

Can they stop the sinister force that controls the train before it’s too late? Can they solve the mysteries of the train, and with them, learn the secrets of the universe?