Callum and Sephy have grown up together, best friends, and now in their teens maybe their friendship is developing into something more. But there is a problem, Callum is a Nought, and Sephy is a Cross, and the two don’t mix, not in this world. But there are moves towards progress and integration, or at least hopes of that in the future; for the first time noughts will be allowed into Sephy’s school, and Callum is one of the four that managed to pass the entrance exams. He will be allowed in, but he knows that it will be difficult, Sephy is more innocent. She’s just glad they’ll be able to spend more time together. Neither knows just how hard it is going to be, and all that is before the bomb goes off.