Doctor Omega, is the mysterious inventor of a spacecraft called the Cosmos, which left Earth from Normandy, France, and made it to the planet Mars in 1906! Doctor Omega is accompanied on his journey by his neighbor Denis Borel, and his worker, the hulkish, Fred. Doctor Omega and his two companions travel to Mars, where they first land in one of the Martian seas, where they perform some underwater exploration during which they encounter phosphorescent fish and aggressive reptilian mermen. Back on the surface, they are attacked by savage dwarf-like beings with long, tentacled arms.