The greatest adventure of his life begins for Checker Tobi on a pirate ship in the middle of the sea. There he discovers a message in a bottle containing a riddle. If he solves it, he will reveal the ...

Tobi revisits an old childhood riddle: Who leaves the deepest traces in the earth? His search takes him to places like Madagascar, Spitsbergen, and Mexico, where he uncovers what connects them and ...