Rod Spencer participates in a zoological expedition to Venus, led by his beloved's father, Dr. Everton. Everton believes that Rod does not deserve his daughter's hand in marriage because he is nothing. To prove him wrong, Rod decides to catch a mysterious six-legged turtle, which people call the Six-Legged Svengali. No one has yet managed to catch this turtle, because as soon as a person meets it, he is overtaken by temporary memory loss. Rod Spencer comes up with a cunning plan, thanks to which he will catch the turtle, because only after this he will be able to marry the daughter of Dr. Everton...