This gripping adventure story is packed with eccentric characters, thrilling secrets, amazing inventions and breathtaking surprises. Sam's holiday with his friends Zara and Ben is interrupted when a bedraggled traveller blows in on a storm, reawakening a mystery from their Great Uncle Alexander's past. For thirty years, the remote Arctic island of Nordbergen has remained desolate and uninhabited. Now, strange aircraft have been seen landing and armed guards patrol the island's fringes. Professor Murdo has returned to Nordbergen to complete his secret and deadly work. Sam, Zara and Ben embark on a desperate rescue mission to the frozen Arctic Ocean. To make the journey, they must discover one of the most extraordinary secrets in the world. To survive, they must rely on their courage, their ingenuity and the assistance of strangers.