who explain the situation: they are in Atlantis. Indeed, 12,000 years ago, Atlantis ruled the world from an island in the middle of the Atlantic. But the collision between Earth and a huge celestial body caused the immersion of the continental coasts and island. The few survivors of the Atlantean civilization then decided to build a new and secret Atlantis in the bowels of the Earth. Since then, the Atlanteans, much more evolved than the inhabitants of the surface thanks to the immense energy source that constitutes the orichalcum, watching the surface of the Earth thanks to what earthlings call flying saucers. So that Blake and Mortimer are starting their new lives in Poseidopolis, capital of Atlantis, they are victims of murder attempts. He then appears to Icarus that Atlantis is threatened with a serious danger. To confirm his suspicions, he went secretly, accompanied by two earthlings, to the great gate that separates the Atlantis of the Kingdom to the barbarians. These are the descendants of wild peoples who lived on Atlantis and Atlantis were greeted in their underground area, now rejected in a territory behind the Great Gate as a result of attempts to revolt. The three men have reason to be wary as Magon, the phulacontarque, is the head of a conspiracy which, with the help of the barbarians, intends to overthrow the Basileus and invade the Earth's surface. Having got wind of the departure of Icarus and fearing the discovery of its projects, mago tries to destroy the shipment, but Blake, Mortimer and Icarus to survive. They arrive finally at the Gong sacred, above the great gate and tower which was once used to prevent Poseidopolis of a barbaric attack. That's when Magon and an escort of conspirators through this place to visit Tlalak, the King of the barbarians. The latter is recommended by Olrik, who, having suffered a fall in the cave, found himself at the Court of the King, seeing in this post to advise an opportunity to take revenge on men. But while Magon and Tlalak to discuss the terms of their alliance, Blake, Mortimer and Icarus appear, who took the identity of members of the guard of Magon in the sacred Gong. The three friends fled and split: Blake tries to warn Poseidopolis directly while Mortimer and Icarus take the low road. At the inland sea, Blake steals a boat to reach the