Brick Bradford is assigned by the government to aid Doctor Gregor Tymak, scientist and inventor who is working on an "Interceptor Ray" that can destroy incoming rockets. Unfortunately, it can also be used as a death ray, bringing it to the attention of foreign spy agent Laydron. Tymak uses his door into the fifth dimension to escape criminals and it takes him to the far side of the Moon (which luckily has air and is a rocky terrain without craters). There he is captured and sentenced to die by freezing to absolute zero by the Queen Khana, despot of the Moon, because they do not believe he has come from the Earth. The action moves to the Moon as the ray requires a special element called Lunarium (with an atomic mass of 200) previously only found in a meteorite. Working with exiles in the lunar wasteland, the heroes overthrow Queen Khana and return with the Lunarium. However, the device still requires a formula hidden on an uncharted island 200 years in the past, so Brick and sidekick Sandy Sanderson travel in Tymak's time machine, the Time Top, to retrieve it. The final third of the serial is spent on modern day Earth with more trouble from the spy Laydron.