Atlantis Mystery (l'Énigme de l'Atlantide) by the Belgian artist Edgar P. Jacobs was the seventh comic book in the Blake and Mortimer series, first published in Tintin magazine from March 30, 1955, to May 30, 1956.

During a speleological expedition deep in the caves of the Azores, Blake and Mortimer are cut off by their old enemy Olrik, trapping them in a gaseous cavern.

While exploring a hole called by locals "O furo do Diabo", he finds a radioactive rock and cannot help making a rapprochement with the orichalcum mentioned by Plato, the mysterious metal of Atlantis, this legendary civilization so-called swallowed up by the waves.

Indeed, a foreign power, having intercepted the letter from Mortimer to the address of Blake, is interested by this potential source of nuclear energy and Olrik hired to retrieve the rock.

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.

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.

At the inland sea, Blake steals a boat to reach the capital, but, caught in a typhoon, it is brought back to its starting point where he is captured by the conspirators.

At the Palace, Magon finally unveils his coup in the Basileus as the King Tlalak and Olrik, followed by a horde of barbarians, enter the command room.

While Atlantis prepares to join other skies, barbarians, Tlalak, Magon and Olrik are facing the rising waters, and Blake and Mortimer are released and evacuated by a submarine remotely piloted by Icarus.