A malevolent alien brain, bent on world domination, takes over the body of an atomic scientist, while a 'good' alien brain inhabits the body of the scientist's dog and waits for an opportunity to defeat the evil brain.
| Actor | Role |
|---|---|
 John AgarSteve March | Steve March |
 Joyce MeadowsSally Fallon | Sally Fallon |
 Robert FullerDan Murphy | Dan Murphy |
 Thomas Browne HenryJohn Fallon | John Fallon |
| HHenry TravisColonel Frogley | Colonel Frogley |
| EE. Leslie ThomasGeneral Brown | General Brown |
| TTim GrahamSheriff Wiley Pane | Sheriff Wiley Pane |
| BBill GiorgioRussian | Russian |
 Ken TerrellColonel in Conference Room | Colonel in Conference Room |
| DDale TateProfessor/voices of Gor & Vol (uncredited) | Professor/voices of Gor & Vol (uncredited) |