Young reporter-in-training Kate and her mouse-accomplice Rupert are on board a train, to visit Kate’s mum in the Arctic. But as soon as the train departs, mysterious things start happening.

A packet of ginger nuts goes missing… A collection of gymnastics trophies are stolen… And some ancient scrolls disappear…

Fellow passenger Madame Maude seems the most likely culprit, until a surprising – and delicious – twist turns the whole investigation on its head.