La piramide sommersa

Following the trail of a virus that will destroy the memory of all electronic computers in the world, unless the requests of a mysterious blackmailer are fulfilled, Martin reaches the legendary Santa Claus, who comes to his aid thanks to an ancestor of computers: Charles Babbage's steam analytical engine. And after a computer puzzle, for Martin it's time for a new adventure, this time set in the waters of the Mediterranean and those of the Gulf of Mexico.