Maj. Gordon Towers William Leslie and Capt. Webber Carl Crow return to Space Station X-7 after gathering geological samples and ice from newly discovered Moon ice caves. The homeward leg is tense but uneventful until Webber suddenly collapses, and the crew rushingly carries him to the infirmary, where Dr. Hoffman begins a careful, puzzling examination. The station hums with activity as Towers is joyfully reunited with his girlfriend, the civilian biochemist Faith Montaine Dolores Faith, whose expertise will soon be crucial to understanding a mystery that could threaten everyone on board.
Dr. Faith Montaine notes a troubling clue—a small welt on Webber’s leg that quickly grows into a spreading fungus. Her instinct points to the Moon’s ice caves as the possible source of the spores, prompting the team to place Webber in isolation while they investigate the bizarre infection. The atmosphere aboard X-7 grows increasingly claustrophobic as the fungus advances, and Hoffman's diagnostic caution hints at a danger far beyond a simple space illness.
Meanwhile, the station’s commander, Col. Frank Cromwell Richard Garland, begins to behave with unsettling oddity. As a swarm of meteors closes in, his hesitation to issue evasive maneuvers becomes apparent, and he is only nudged toward action by the ship’s communications officer, Lt. Connie Engstrom Pamela Curran. The mounting tension within X-7 mirrors the external threat from space, while the fungus tightens its grip on the crew.
Tragedy strikes when Webber dies, his body horribly disfigured by the fungal growth. Cromwell studies the corpse with eerie calm and mutters, “There’s nothing unusual in there,” refusing to report the death to Gen. Knowland on Earth Control Center. He warns Towers, Faith, and Hoffman to keep silent about the fungus lest panic rip through the station. Hoffman's cautious inference is blunt: Cromwell is on the verge of space raptures, a serious illness masquerading as steadfast leadership.
To counter what he sees as mutiny, Towers attempts to remove Cromwell from command, but Cromwell calls it mutiny in return. The confrontation escalates as Connie covertly records the mutinous orders and transmits them to Earth. Knowland detects the anomaly—space weapons had been outlawed since 1970, long before X-7’s mission—and recognizes that a broader threat could be at stake. If the fungus spreads to Earth, drastic, even devastating, decisions may be required to prevent catastrophe.
As the infection worsens, Hoffman's condition worsens too, and he becomes gravely ill. Yet he manages to convey a crucial fact to Faith and Towers: the fungus can be killed by cold. With this new knowledge, the team makes a renewed, perilous effort to regain control of X-7. Cromwell, now fully gripped by space raptures, sabotages communications and escapes confinement to threaten the ship once more, a desperate act that is quickly followed by recapture.
The turning point comes with a daring plan: to lower the interior temperature of X-7 below freezing. Freezing the fungus inside would effectively halt its growth. The unexpected twist, however, is that the fungus then begins to spread on the outside of the station. A staff officer explains that the heat from the unshielded Sun is driving the exterior growth, a clue that reframes the crisis. Gen. Knowland devises a bold counterstrike: launch a rocket to create a cloud of ice crystals—an icy corridor for X-7 to pass through, silencing the growing fungal threat.
The risky maneuver succeeds. As the interior chill takes hold, the fungus on the exterior is killed, and the station stabilizes. With the critical systems repaired, Towers reestablishes contact with Earth and requests a relief ship. Knowland confirms the three-hour window for rescue and offers a hopeful closing line: “Don’t lose your faith.” Faith and Towers exchange a quiet, relieved glance, their bond strengthened by the ordeal, signaling the end of the crisis and the endurance of the human spirit against the unknown perils of space.
