Meet Piotr, Minnie, Andrew, Flora and Sylvie - true friends and even better mystery-solvers! When Minnie's gran comes to stay, all the way from Nigeria, Minnie KNOWS there will be trouble. And straight away Gran notices she's picked up the wrong suitcase at the airport. This one is full of boy's clothes, and she's not at all happy about it! But when their house is burgled and the only thing taken is the suitcase, Minnie realises there'll be much more trouble than she bargained for.