| Director | Arthur C. Pierce, Hugo Grimaldi |
|---|---|
| Genre | science fiction film |
| Runtime | 87 min |
| Country | Italy, United States |
| Budget | $90,000 |
Maj. Gordon Towers and Capt. Dan Webber are returning to Space Station X-7 after collecting geological samples and ice from newly-discovered ice caves on the Moon. Upon arrival, Dan collapses and is taken to the infirmary by Dr. Hoffman and Gordon is reunited with his girlfriend, Dr. Faith Montaine, a civilian biochemist.
Hoffman has difficulty diagnosing Dan, ruling out "space raptures" because they cause hallucinations and not the high fever that Dan is running. Faith notices that a small welt on Dan's leg is growing rapidly into a large fungus. She says that the spores causing the fungus must have come from the Moon's ice caves. They put Dan into isolation.
Meanwhile, the commander of X-7, Col. Frank Cromwell, is behaving oddly. As a swarm of meteors approaches the space station, Cromwell is unable to give the order to take evasive action until prodded to do so by X-7's communications officer, Lt. Connie Engstrom.
Dan dies, his body horribly disfigured by the fungus. But when Cromwell looks at the body in the isolation chamber, he calmly says, "There's nothing unusual in there" and refuses to report to Gen. Knowland at Earth Control Center that the fungus has killed Dan. He insists that Dan's demise was caused by "pressure shock" and warns Gordon, Faith, and Hoffman to say nothing about the fungus because it might panic X-7's crew. Hoffman says that Cromwell is "on the verge of space raptures" and very sick.
Gordon decides that the situation is serious enough to remove Cromwell from command. But Gordon fails in his attempt, which Cromwell says is "mutiny". Cromwell orders Connie to send a message to Knowland about the mutiny and to say in it that Gordon held the crew at gunpoint until he was overpowered. Connie seemingly agrees, but Cromwell does not know that she has surreptitiously recorded the order. She transmits it to Knowland, who is immediately aware that something is amiss because weapons were outlawed in space in 1970, more than 20 years earlier. Connie also reports that the entire space station is being overrun by the fungus. Knowland tries to reply to X-7 but gets no response. He says that X-7 may have to be destroyed to prevent the fungus from reaching Earth.
Hoffman contracts the fungal infection and is very ill. However, he is able to tell Faith and Gordon that the fungus can be killed by cold. Knowing this, Gordon and the others make a second attempt to take control of X-7. Besides the danger from the fungus, Cromwell, now fully in the grips of space raptures, is trying to destroy X-7. They confine Cromwell to his quarters, but he escapes and sabotages the communications system, cutting off all contact between X-7 and the Earth. He is then recaptured.
Gordon knows that the only hope of saving X-7 is to lower its interior temperature to below zero degrees. The fungus inside X-7 dies, but it is now growing on the outside of the space station. No one can understand why the fungus is spreading on X-7's exterior until one of Knowland's staff officers says that it must be due to the "high temperatures generated by the unshielded blazing sun" beating down on X-7. This gives Knowland the idea of launching a rocket that will explode and form a huge cloud of ice crystals for X-7 to pass through.
Knowland's idea works and the fungus on the exterior of X-7 is killed. Gordon uses the repaired communications system to request a relief ship. Knowland tells him that it will arrive at X-7 in three hours and concludes his message by saying, "Don't lose your faith". Faith and Gordon look at each other and smile now that the crisis is over.