Emma and Abby were once best friends. they spent all their time together, laughing and having fun - until something terrible happened. Nobody knows what - Emma never talks about it.Emma has new friends and barely thinks about Abby. But then Abby dissapears. Emma bumped into her on the bus that day - and was the last person to see her before she went missing.Why is Emma being so secretive?And what on earth has happening to Abby?