However, their budding romance is quickly put on hold as the station's scientists learn they must deal with a rogue planet—"The Outsider"—that has entered the Solar System, and which is on a collision course with Earth.

As the exploratory spacecraft approach, a number of disc-shaped alien spaceships emerge from beneath the planet's surface, destroying the Earth vessels.

Benson's expedition discovers a race of humanoid creatures dead at the controls of their planet-spaceship, as the automated systems continue their work without purpose.

As the exploratory ship returns to Earth, Commander Cole speaks Benson's epitaph: "Poor Benson—if they'd opened up his chest, they would only find a formula where his heart should have been".

"[3] Writing on Trailers from Hell, critic Glenn Erickson described the film as "toy rockets, overripe dialogue and thunderous acting from Rains [...] leading to a finale in an ‘alien brain cave’ made of colored plastic tubes," adding that the film "manages to squeak by, flimsy production short-cuts and all," and that "this critical ‘triumph of the imagination’ indeed makes something entertaining out of very, very little.

"[4] A review in TV Guide reported that "this far-fetched space yarn is saved somewhat by Rains's performance" and that "impressive sets and sharp direction by Margheriti offset a docile cast, contrived dialog, and poor English dubbing.