Tyko Flores is a boy, soon to turn fourteen years old, who has spent all of his life in slavery down in the silver mines accompanied by other orphans.
One night Tyko dreams about a magpie that passes him a mysterious riddle about a curse that can be broken in a square to absolve a mother’s grief. Tyko doesn’t understand the dream but it keeps haunting him. Soon Tyko to his great surprise learns that somebody wants to meet him above ground. Tyko decides to escape from the mines to meet this mysterious somebody. Unexpectedly he’ll be accompanied by another orphan: skinny and determined Julius.
Once up on the ground Tyko and Julius are taken into a secret society of Geographs where they learn that the Geographs have found three worlds but don’t know how to travel between them: their own world Communae Sphaere, ruled by Count Mazoo, the dreadful Dancing Devil, the second world The World of the Red Road and the third The Dark Planet. Tyko is given a book which will later save his life and a sealed letter that is addressed to him to be opened on his fourteenth birthday. The book tells Tyko to hurry to The Square of Two Brothers. Bit by bit Tyko understands that the strange riddle the magpie told him in his dream and the book are both speaking about him and his mother.
Tyko and Julius start a dangerous and difficult journey to find the square which is said to exist in one of the three worlds. First they need to find the secret passage to enter the next world. In order to do so, Tyko and Julius get the help from three animals, the magpie, a rat and a toad.