When Wendy Midwinter’s grandfather is on his deathbed, he tells her he has been the guardian of a tome for a very long time, one that has all the weather inside it. As his last request, he asks her to take it to Mr Allbright, the new chief weatherman at the Exeter Weather Station. Wendy finds the book as he requested, and the next day, she and her friend Raine take it with them to the Weather Exhibition at the Exeter Station. The exhibition is packed, however, so the two girls go up to the roof—where Wendy is suddenly snatched away by a tornado! She finds herself whisked away to Heligoland, a cloud castle situated at the heart of a low pressure front barely rising above the Irish Sea and the home of the Foul Weather-Makers. Imprisoned in the dungeons there by German Bight, the castle genius, Wendy must find her way home in order to warn people about the urgent changes needed to save the planet. In this novel, a girl comes into possession of a magical tome that grants the power to create extreme weather and ends up in the middle of a war over weather and climate change.