After stowing away on a rescue helicopter, three children find themselves stuck on a remote island in the Arctic Ocean with little hope of rescue. They have to conquer fear, wild animals, raging weather, lack of food, and find a way to communicate with the mainland.

Mysterious holes in the ground appear during the night, causing Oliver's bicycle to be destroyed. Who made these holes and why? The child detectives Tiril and Oliver will have to be as smart as Sherlock Holmes to find out.