When sixteen-year-old Lillie Hart meets the gorgeous and mysterious Tom Windsor-Smith for the first time, it's like fireworks - for her, anyway. Tom looks as if he would be more interested in watching paint dry; as if he is bored by her and by her small Nebraskan town in general.

But as Lillie begins to break down the walls of his seemingly impenetrable exterior, she starts to suspect that he holds the answers to her reoccurring nightmares and to the impossible memories which keep bubbling to the surface of her mind - memories of the two of them, together and in love.

When she at last learns the truth about their connection, Lillie discovers that Tom has been hiding an earth-shattering secret; a secret that is bigger - and much more terrifying and beautiful - than the both of them. She also discovers that once you finally understand that the world is round, there is no way to make it flat again...