After leaving China under the threat of Zares, our heroes finally arrive in Japan. They must absolutely find there the third City of Gold against which the infamous Zarès promises to release Athanaos, the father of Esteban.
Esteban, Tao and Zia is Yoshi, an old man who keeps fiercely the impressive Orichalcum sphere. Yoshi reveals to the children that it is a sacred object, rejected by the sea thousands of years ago and revered since as a gift of the gods .
Using his gift to make the sun reappear, Esteban allows Zia to take off the Condor. Under the astonished eyes of Yoshi, the immense golden bird finally emerges from the waves. Mendoza, Sancho and Pedro manage to escape from the castle.
At night, as Ichiro goes to take his guard duty at the castle, Esteban follows him and tries to convince him to help him to escape Mendoza and his men. Ichiro refuses.
Mendoza and his men takes control of the nave and makes the prisoners Gaspard and Ambrosius. They spot the Condor and rediscover the children Mendoza reveals to them the betrayal of Ambrosius who delivered them to Shimazu.
Ambrosius claims that it was Mendoza who assaulted him, but he loses his compass, which Esteban picks up and tends to him Suddenly, the young boy realizes: this compass should be in the possession of Zares.
In the center of the cave, at the top of a pyramid, our heroes discover a sphere of orichalque floating on a lake. Attacked by thousands of giant crabs, they manage to take refuge inside. What turns out to be a ship.
The pursuers turn out to be children whose parents were abducted by the men of Ambrosius to work forcibly at the Fort of Pattala. When they learn that our heroes are not friends of Ambrosius they decide to unite to free them all.
At the fort of Pattala, Esteban is spotted by Ambrosius. When escaping, he sees his father in a cell but must flee because he is persecuted by Laguerra, the right arm of Ambrosius, and the guards of the palace.
Tao is now in the hands of Ambrosius. The latter tries to return to his good graces, but Tao sees him as a traitor and refuses to give him his confidence.
Laguerra and the soldiers find only a deserted village. Laguerra spots the children hidden in the trees. She hesitates, but does not denounce them and leaves without saying anything with her men Mendoza decides to act fast.
Our heroes are surrounded by a troop of Bedouins. Their intrigued chief observes the medallion When the children leave, he asks a young boy to follow them to find out what they are doing in Ormuz.
Esteban is worried about what happened to Mendoza and his men, but his friends remind him that Mendoza is resourceful and their priority is to prevent Ambrosius from appropriating the muen knowledge and make it Weapons of war.
The children finally manages to penetrate inside the ziggurat. They start their descent in search of the sacred sails of Princess Rana'Ori in the bowels of the pyramid.
Zarès aided by Laguerra captures the children and pushes them towards the exit, revealing to them that he possesses, anyway, another track towards the fourth city of gold. They just need them and their medallions to open it.
In the desert, the suspected noises heard are produced by none other than Sancho and Pedro lost in the dunes. They finally found their friend Mendoza. The children try to leave the oasis to reach the Condor.
Laguerra prevents Gaspard from killing Mendoza, arguing that Mendoza will be more useful to their living plan than dead. The children enter the city in search of the tomb of Princess Rana'Ori, but the sumptuous city seems deserted.
