Harcourt Brown (George Coulouris) has tricked everyone into believing that Captain Wilson (Graydon Gould) has landed on Venus. Still on their rescue mission Conway Henderson (Gerald Flood) and the rest of the team decide they must land as well even though they have no idea what they will find. The planet is covered by a poison cloud that they must descend through. Once they clear the clouds, they can see vegetation. They land in a forested area near a swamp.
Brown fully believes that the air underneath the clouds is breathable. He leaves the ship without his helmet. Henderson and Mary Meadows (Pamela Barney) also leave the ship but with their helmets on. Geoff (Stewart Guidotti) and Margaret (Hester Cameron) remain in the ship to man the radio. They find that indeed the air is breathable. They head off looking for Captain Wilson’s ship.
By now Captain Wilson’s orbit of Venus has decayed and he is quickly running out of air. He must land on the planet’s surface himself. Geoff detects the rocket landing. He tells Henderson about it, but Henderson believes that Wilson is already on the planet surface, so he assumes that Geoff is seeing a meteorite or some other explainable phenomenon.
Geoff and Margaret decide to leave the spaceship and check out what landed. They find Wilson’s ship but no Wilson. The inside of the rocket has been damaged by some unknown creature. Something from the forest.
Having breathable air on Venus is a bit of a stretch. By the time we get to the last of the series the idea of having the stories based in fact has flown out the window and fantasy has taken over. That’s all to the better. There are still tidbits of science information being weaved in but as far as what Venus looks like, the emphasis is heavy on the fiction part of science fiction.