Junior and Barney are taken to a planet ruled by a brain-controlling compuser named G.A.L. 36-24-36.
The boys land on Crystallitis, a planet populated by glass people. Junior is appointed the new king, but learns he'll have to be turned into glass to qualify.
To rescue Princess Lantana of the underground city of Pod, the boys must retrieve a magic belt from the planet's evil ruler, the robot Mercurial.
A mad scientist makes the mistake of his life by appointing Junior and Barney as his assistants.
Barney and Junior are branded bad guys by a power-hungry tyrant, who has seen their arrival in his future machine and made them pawns in his bid to become ruler. While Junior and Barney are on another planet, he imprisons the beautiful Queen of the Serrians high in the Tower of Tagot. Naturally, the Space Nuts must come to her rescue.
Mistaken for underground hero Junio, Junior is compelled to resue Queen Helona of the planet Sporia from Troyak's crystal ball prison.
Junior and Barney arrive on the planet Vultron, inhabited by a race of bird people. The bird people capture the Space Nuts and force them to sit on an enormous egg until it hatches.
Junior and Barney get tricked into trading their ship for a mysterious hexagon key that supposedly operates a duplicating machine, which can make the Space Nuts a new spaceship to get home.