MR-1, Moon Rocket-1, the first spaceship sent from Earth, landed safely on the planet’s surface. MR-2, containing Conway Henderson (Gerald Flood), Jimmy Wedgwood (Richard Dean), Valerie Wedgwood (Gillian Fergusson) and Geoffrey Wedgwood (Stewart Guidotti) is orbiting the Moon when an alien spaceship is seen. The alien ship is on a collision course with MR-2. With some special piloting and some fancy footwork, MR-2 manages to avoid the collision and land on the Moon; however, it is 150 miles away from MR-1. MR-2 is unable to communicate with MR-1, but it can talk to Earth.
The team from MR-2 decides to put a radio transmitter on a nearby ridge to get a better signal. While walking toward the ridge Jimmy finds a symbol or hieroglyphic carved in a rock. Back at MR-1, Professor Wedgwood (Peter Williams) and his team head out to rendezvous with MR-1. They too find symbols in a rock.
After they position the radio transmitter Henderson and the kids head back to MR-2. They don’t get very far when Jimmy falls into an air shaft in the Moon’s surface. Turning on his flashlight he finds what appears to be another alien spaceship.
Although the series tries to present space facts as much as possible there are problems with trying to mimic Moon activity when, at the time, no one had been on the Moon. To explain why people aren’t bouncing around the Moon with it’s one sixth the gravity, Henderson explains that their spacesuits are heavy enough to compensate. That would make the suits on the Earth six times as heavy. Neil Armstrong’s suit, with him in it weighed 360 pounds on Earth but only 60 pounds on the Moon. To compensate enough to walk normally on the Moon the spacesuit of a 180-pound man would have to weigh somewhere around 900 pounds on Earth. Man and suit would tip the scales at 1080 pounds. Although a completely outfitted spacesuit is heavy, it’s not that heavy.