I would highly recommend Noughts and Crosses by Malorie Blackman because its a captivating book to read about how two families who once were friends The Hadley family (crosses) and The McGregor family (noughts) they were really good friends before they ended up becoming enemies and hating the each other their children Callum and Persephone (sephy as Callum called her) who were childhood best friends.

If you want to find out more then I suggest you read the book.