La nave volante

The Atlantean city of Ol Undas, hidden for millennia on top of a very high rock, was destroyed (and all its citizens killed) by the artificial monsters created by Saltur. The scientist wanted to create his own army of monsters to seize power and conquer the world. To defeat the monsters who remained on the stone tower, led by a primate-like chief called Serkis and apparently endowed with superior intelligence, Zagor and Scarlet (the adopted daughter of the aviation pioneer, Icaro La Plume) drive a flying machine devised by the Baron to Ol Undas, escorted by a military squad.