Ophir

Having rid themselves of the threat of Magon the Olmec, the children are hot on the heels of Ambrosius who has opened the city of Ophir thanks to his medallion. A bitter fight for the city's treasure begins: the stone of Ophir, also known as the philosopher's stone. Meanwhile in Chambord, Nostradamus shows Tao the treasure of Chambord: a double-helix staircase designed by his master Leonardo da Vinci. But what secret does it hide?