It's the summer holidays and Millie's bored stiff Every week, she has to clean windows with her dad at a nearby laboratory But she's sure something weird is going on inside Then, one day, a cat comes hurtling through the lobby towards her and asks her for help And Max needs a lot of help He's trying to escape, he wants to know who kidnapped him, and why - who on earth would want to make cats that can talk? And he needs Millie to help him rescue the friends he's left behind before it's too late