On a mission to Jupiter, Slim disappears in the swamps. Raeburn orders Dart and Husky to leave but trouble with the Galasphere's primary drives gives Dart an excuse to resume the search only to find that Slim has shrunk to dwarf-like proportions

Raeburn is contacted by Yria from Alpha Centauri who is seeking help to destroy an evil computer superbrain which is attempting to take over the planet Delta

The Galasphere is sent on a rain-making mission to Mars with a cargo of oxygen and hydrogen—the very ingredients escaped criminal Marog requires to complete his bomb under construction at his Phobos hideaway

The Neptunians create a forcefield around the Earth containing particles with strong electromagnetic properties. The field begins disrupting electricity supplies, causing a complete blackout

Saturn has a new leader. Riga is succeeded by his brother Simba and whilst Dart is en route to investigate, Simba launches rockets destined for Earth containing Saturnian grass seed—which absorbs oxygen and emits carbon dioxide

The Galasphere's Meson unit malfunctions and lands in the unexplored Tuhera jungle. Dart and Husky leave to fix the problem. When Husky fails to return, Dart follows and is captured by a giant primitive man. Husky speaks with the giant in its native language and they are set free. They return to Earth with some Martian fruit which makes hair grow—the perfect solution to Haggarty's problem

Tyrig plans to use a nerve gas to seize power on Mars. Raeburn discovers that Tyrig and his men have set up base on the Martian moon Phobos and Dart is sent to investigate. Dart and his crew are captured by Tyrig, who wants to use the Galasphere to spread the gas. Refusing to co-operate they are placed in a dungeon which slowly fills with sand

A strange jittering is affecting the city and other Earth locations. Haggarty discovers, by chance, that the jittering is caused by radio waves emitted by Uranus, where the Duos are once again planning an invasion