An alien named Andros arrives on Earth to study it and to convince the intergalactic council that the planet should not be destroyed because of World War II. The American government first suspects Andros of being a Nazi spy and the Nazis want to use Andros's powers for world domination. Wonder Woman and Andros must work together to prove America's intentions are peaceful, as Andros at first is not sure if either side is right (mentioning the internment of "Americans of Japanese descent" in reply to Wonder Woman's charges against the Nazi racial policies). While exploring the Library of Congress, Andros is stripped of his powers and captured by the Nazis. Wonder Woman tries to save him but faints after being hit by gas. The intergalactic council decrees that if he is killed the Earth will be destroyed.
Wonder Woman journeys to Germany to rescue Andros. After seeing that she is prepared to sacrifice her life to save him, and when Steve Trevor demonstrates that the Allied cause is just, the aliens relent on their threat to destroy the planet. Andros invites Wonder Woman to accompany him in space, but she replies that she is needed on Earth. Andros promises to return to see her in 50 years.