Macius was 9 when he became king of a small country. The young Macius quickly realizes that running a kingdom is not child's play, especially when the general of the armies tries to take advantage of his naivety.

Following the sudden death of his father, King Stéphane, Macius must succeed him. Alone in the world, a frail figure barely nine years old for an ermine coat too big for him and with his only friend Erasmus tutor, Macius, at first, does not feel able to ascend the throne. This is the perfect opportunity for the general to attempt to seize the Crown. He has Erasmus removed by his special agent Passe-Partout.