In the episode, the Enterprise pursues a vessel and rescues its occupants Harry Mudd, an interstellar con man, and the three mysteriously beautiful women he is transporting to become the wives of settlers.

The three women who accompany him are stunningly beautiful, and they distract the male crew members of the Enterprise, excluding Mr. Spock, whose Vulcan heritage makes him immune to female charms.

The women are intended as wives for settlers on the planet Ophiuchus III and are introduced as Ruth Bonaventure, Eve McHuron, and Magda Kovacs.

Kirk convenes a hearing, during which the computer contradicts Walsh's testimony, reporting that his ship master's license has been revoked and forcing him to reveal his true name, Harcourt Fenton Mudd, a criminal with an extensive record.

At an impromptu party with the three miners, Eve becomes angry when they begin fighting over the other two women, and runs away into a magnetic dust storm, with Childress and Kirk in pursuit.

The captain reveals that Mudd has been giving the women the Venus Drug, which creates a transient, illusory beauty, and that the other two miners have already been married to Ruth and Magda.

Several weeks later Kandel presented his idea, "Mudd's Women", and started to write the script but disliked that Roddenberry repeatedly rewrote it.

[5] In 2016, TVLine ranked Eve finding out Kirk had given her a placebo rather than the beauty pill as number 13 on the top twenty moments of Star Trek: The Original Series.