Nearing his twelfth birthday, Brendan, together with his younger brother Ryan and friend Gabrielle, discovers a mysterious golden object in the Maine woods. To their amazement a ghostly voice from within entreats them to save the world from McGrab, a horrifying creature who wishes to conquer the planet. Before they know it, the three children cut through the earth's crust in a magical sphere as they try to stop McGrab. Confident of victory, McGrab toys with his adversaries, leaving clues about what they must seek across the globe in order to stop him. Traveling from continent to continent amid hair-raising adventures and thrilling escapes, the children solve his cryptic puzzles. Along the way, they discover surreal places and stunning geography: a pink lake, a building capped with giant eggs, and an island that arises in a single day. Armed with knowledge about the world and themselves that they've gained in their wild chase, the children return home to face McGrab in a decisive battle in which the fate of the world hangs in the balance.