Aliens have landed and are hiding on Earth, but need Earth’s scientists to help them fight an inter-planetary war.
| Actor | Role |
|---|---|
 Rex ReasonDr. Cal Meacham | Dr. Cal Meacham |
 Faith DomergueDr. Ruth Adams | Dr. Ruth Adams |
 Jeff MorrowExeter | Exeter |
 Lance FullerBrack | Brack |
 Robert NicholsJoe Wilson | Joe Wilson |
 Russell JohnsonSteve Carlson | Steve Carlson |
 Douglas SpencerThe Monitor of Metaluna | The Monitor of Metaluna |
 Karl Ludwig LindtDr. Adolph Engelborg | Dr. Adolph Engelborg |
 Regis PartonMutant (uncredited) | Mutant (uncredited) |
 Richard DeaconPilot (uncredited) | Pilot (uncredited) |
 Coleman FrancisExpress Deliveryman (uncredited) | Express Deliveryman (uncredited) |
 Robert B. WilliamsWebb (uncredited) | Webb (uncredited) |
| CCharlotte AlpertMetaluna Woman at Decompression Console (uncredited) | Metaluna Woman at Decompression Console (uncredited) |
| SSpencer ChanDr. Hu Ling Tang (uncredited) | Dr. Hu Ling Tang (uncredited) |
| LLizalotta ValescaDr. Marie Pitchner (uncredited) | Dr. Marie Pitchner (uncredited) |