Izzy is really excited to have been put in charge of the new girl, Matilde, at school. Matilde is French, and Izzy and her friends can't wait to show her their den and its moth, and to help her avoid school dinners (more commonly known as poison).

But Matilde LOVES school dinners and even has seconds! And that's when they realise. Matilde is a spy and she has come to find out their secrets. They must stop her before it's too late!