A space mission to Venus discovers a society of Amazons.

In the distant future, astronauts Capt. Neil Patterson, Lt. Larry Turner and Lt. Michael Cruze are assigned to escort Professor Konrad to the outer space way station that he designed years earlier. Although disappointed by their seemingly unimportant mission, the men comply and conduct an uneventful launch into space. As the spaceship nears the station, however, a ray beam, whose origins the men cannot discern, fires repeatedly until it hits and destroys the station. When the beam turns on the ship, Patterson attempts to divert it, but the craft is hit, causing it to spin out of control and crash into an unidentified planet. The men, who are only mildly shaken up, are amazed by the snow-covered mountains surrounding the ship. After a cursory investigation, Konrad declares that they have landed on Venus and, contrary to all earlier hypotheses, the planet supports life. The men descend below the snowline to investigate their surroundings, unaware that they are being watched. The next morning, the men are startled by the appearance of several armed women, who inform them that they are under arrest. The women take the men to a large city, populated entirely by women, many of whom deride the men as they are led to the palace. The men are brought before the masked Queen Yllana and her council, who demand to know why they have come. Patterson describes the destruction of the space station by the strange beam, then requests assistance in repairing their ship. Yllana informs them that her people have monitored earth for many years, enabling them to become familiar with earth forms of communication as well as the planet's extreme violence. Suspicious of the men's explanations and believing they have come to destroy Venus, the queen announces that she and the council will meet to decide their fate. Unknown to Yllana, another member of the court, top scientist Talleah, receives a secret report of the interrogation from her aid, Motiya. Yllana then privately interviews each of the men, but is skeptical of Konrad's assertion that, as no one on earth believed Venus was habitable, they would have no reason to attack the planet. When Turner and Cruze observe that the planet needs the stability of men, Yllana orders them all put to death. Imprisoned in a bare room, the men suspect that the space station may have been destroyed by the Venusians, although Cruze cannot accept that woman are capable of building sophisticated equipment. That evening, Talleah brings the men their dinner as an excuse to talk to them and introduces herself as part of a growing group of women who have become disenchanted by Yllana's cruel leadership. She explains that a decade earlier there were men on their planet who engaged in war with a neighboring planet that very nearly destroyed them. Disgusted by the violence, Yllana led the women in a revolt and all the men except the most intelligent, who are kept on a small prison satellite in space. After Talleah's departure, the men decide to overpower Yllana and the women by seducing them. Later, Yllana grants Patterson an audience to meet her in her private quarters. Although Yllana initially admits the loneliness of leadership, she soon presses to know the real reason for the men's arrival, insisting that the space station was an attack post. Patterson maintains the men's innocence and demands to know why she does not respond to him as a man. Curious about Yllana's mask, Patterson snatches it off to discover that Yllana's face is horribly disfigured by radiation burns that the queen tells him were the result of men's wars. When Patterson recoils in revulsion, Yllana orders him to be removed and immediately put to death. Learning this, Talleah arranges for the men to be smuggled to her laboratory. There she informs them she has learned that Yllana has also ordered the destruction of earth with the beta-disintegrator that destroyed the space station. Talleah and her sympathizers offer to help the men escape if they will assist them in destroying the disintegrator. Narrowly averting capture by Yllana's guards, the group flees outside, where they seek refuge in underground caves. When Konrad realizes the walls of the caves are made of gold, Talleah says the mineral has no value on Venus. The next morning Konrad reports that without food and water, the men will not survive. Patterson devises a plan to have Talleah, Motiya and Kaeel, who have not been linked with their escape, turn them in after which they will receive nourishment and then attempt to destroy the disintegrator. The plan succeeds, and while Talleah organizes more support, Yllana prepares to destroy earth. Yllana takes the men to the beta-disintegrator to observe earth's demise, unaware that Motiya and Kaeel have successfully sabotaged the machine. When the disintegrator fails, Talleah leads an attack, during which Yllana is killed and her supporters overcome. Weeks later, under the auspices of the new queen, Talleah, the men's ship has been repaired. As the women sadly prepare to bid them goodbye, the men receive a message from earth ordering them to remain until a rescue ship comes, even if it takes a year.