Note: An adventure story teeming with speculative elements : a Lovecraftian atmosphere reminiscent of At the Mountains of Madness, including a forgotten, mysterious underground city below the plateau of Leng, featuring bizarre — not to say alien — statues and frescoes; friendly yetis; and an evil "empire asiate" (Asiatic Empire) regrouping most far-eastern countries and plotting against the rest of the world, thanks to rockets equipped with "stellar statoreactors". This "empire asiate" bears a strong resemblance to Basam-Damdu's Lhassa-based "Empire Jaune" (Yellow Empire), in Edgar P. Jacob's Le Secret de l'Espadon (1950), a famous Belgian graphic novel. Other speculative allusions include a reference to James Churchward's theory about the lost continent of Mu; the name of the Buddhist monk, Lobsang Rabang (echoing that of T. Lobsang Rampa); and the subtitle of the book, "Les cavernes d'acier", a clear hint at Isaac Asimov's Caves of Steel.

Synopsis: After discovering a Buddhist monk's message written in 14th century Tibetan, professor Aristide Clairembart, followed by his friends Bob Morane, Bill Ballantine and Frank Reeves, sets off for the mysterious plateau of Leng in Tibet, which he thinks is somehow connected with the lost continent of Mu. But they stumble upon a secret base of the evil Asiatic Empire, where a world-wide attack is being prepared...