Britain, 1940, the world is at war and 10-year-old twins Harry and Rosie are about to have their world turned upside down . . . Evacuated from London to live with their great uncle in the Lancashire coast, the twins immediately miss home - and perhaps most of all, the tearoom where their mum works, and where the twins spend hours watching the professional dancers whirl round the floor.

As the vibrancy of London life is replaced with stony silences from their Great Uncle and rainy days in the dark, stormy village of Cotterill Cove, a welcome distraction is the upcoming local Christmas dance show. The twins throw themselves into it, determined to do their bit for the war effort - and score a shot at dancing at the famous Winter Gardens in Blackpool.

But when Harry sees strange flashing lights out on the treacherous mudflats one night, he and Rosie soon discover the quiet, remoteness of their new home is hiding some huge secrets . . . and the enemy is a lot closer than they thought.

As Harry and Rosie race to uncover the truth, they discover bravery comes in many different forms - and even in the worst of times, the show must go on.