Polly's birthday has been planned in minute detail and everyone who is anyone will be attending.

But the worst happens - Polly gets chicken-pox and it is all called off. And to make matters worse Horace the hamster dies. The extent of Polly's misery knows no bounds and many entries to her diary catalogue her despair in hilarious detail.

But all is not lost for Polly's birthday does turn out to be a wonderful day after all - and you will have to read to find out why. (Polly's Running Away Book is littered with clues)