What happens in the book noughts and crosses?

The main themes are Love, Hate and Hope, It is ablout a 13 year old girl Sephy who is black(a cross) and a 15 year old boy called Callum who is white (a nought). They want to get together but they cant because of their parents and they dont know if if will ruin their frendship if anything goes wrong. Callum dies at the end of the series but in the end of the book it is left as a cliffhanger so we dont know but this shold help you.