Thirteen-year-old Tess is a Switcher, able to change into any animal at will. No one knows her secret, or so she thinks. But one day a strange, scruffy boy follows her home from her Dublin bus stop. The boy’s name is Kevin, and he’s a Switcher too. Kevin convinces Tess that their powers are needed for something important: stopping the snowstorms that are rapidly advancing from the Arctic. Tess and Kevin will have to stretch their abilities to the very limit in order to save the world from frozen destruction.