Now that Henderson (Gerald Flood) has disappeared, Geoff (Stewart Guidotti) is alone as he makes his way back to MR-4. Brown (George Coulouris) and Wilson (Graydon Gould) are looking for a Venusian city and Mary (Pamela Barney) and Margaret (Hester Cameron) are stuck in MR-4 while some unknown creature is destroying the main cabin. Mary decides to document on tape a message to send to Earth. A quick inspection of the tape reveals Brown’s deception and that he once again conned Henderson into believing his lies.
Geoff makes it back to the spaceship with no incident and finds that the creature has left. Reunited with Mary and Margaret the three decide to look for Henderson. They eventually find him just as a rainstorm begins.
Brown and Wilson find a cave and evidence that one of the life forms on Venus is a Cro-Magnon type of prehistoric human. On the walls of the cave are cave drawings. They also find unusual vegetation in the form of giant man-eating plants. Ever the adventurer, Brown pushes onward wanting to climb over the mountains in search of his more civilized Venusians. Finding that prehistoric humans are on the planet doesn’t stop his conviction that a more advanced human is also just over the horizon. Wilson, still believing that the other crew members of MR-4 are dead, is forced to follow Brown. At least until he falls into a crevasse.
Henderson and Mary find footprints belonging to both Brown and Wilson leading in the opposite direction of MR-4. Mary knows that Brown lied to them about Wilson landing on the planet so it’s a safe bet that he lied to Wilson about which way to go. Knowing that they can’t leave Wilson and take off for Earth they have no choice but to follow Brown and Wilson. Their sojourn leads them to the cave with the prehistoric drawings and the man-eating plant. Not knowing it is flesh eating, Margaret puts Hamlet, the guinea pig, in the middle of it to see if he’ll eat it but finds out that the plant has plans on eating the guinea pig instead. Hamlet gets rescued but lurking behind everyone is the owner of the cave.
There are a couple brief moments of stock footage in the form of a picture of lighting and a couple moments where a boom mike is seen in the foreground. The flesh-eating plant isn’t all that impressive either. These are all little reminders that you are not really on Venus but are in the middle of a low budget children’s program. Not that any of the other special effects are special either. But they are fun.