Wonder Woman receives her golden lasso as a gift from her mother and takes on the Baroness Paula Von Gunther again.
Steve Trevor gets a promotion to the rank of major. While General Darnell goes on a secret mission to London, Steve takes over his post, and retains Lila Brown as his secretary, meaning that Diana Prince has two weeks off. Before she leaves she discovers that Baroness Paula Von Gunther has escaped the police, and Diana worries that Steve could be in danger, though he denies it. Nevertheless, when Diana gets a message from her mother, Queen Hippolyta, via her Mental Radio, she uses her Invisible Plane to return to Paradise Island dressed as Wonder Woman.
When she reaches Paradise Island Wonder Woman discovers that her sister Amazons are competing in a lassoing contest. She dons a mask and enters, winning the contest over the runner-up, her friend, Mala. Wonder Woman reveals her identity and the Amazons celebrate her return.
Meanwhile, Hippolyta, following orders from the Goddesses Athena and Aphrodite, instructs her craftswomen to use links from her magic girdle, which gives the Amazons their power, to form a rope. She then gives the rope to Diana and tells her that anyone that she lassos with it will be compelled to obey her. Diana uses the Lasso of Truth on Mala to prevent Mala from following her back to Man's World. Diana then uses the Magic Sphere to discover Baroness Von Gunther's location.
As she flies back to the U.S. Wonder Woman learns that a bomb exploded in Steve Trevor's old office, but that he is safe since he was in Colonel Darnell's office. Wonder Woman races to Steve to find him safe, but she learns that Colonel Darnell's ship has disappeared.
The story then tells how Baroness Von Gunther escaped her captivity and invented an invisible ray. She assumes the identity of a Lady Chumpley who was aboard the Gigantic - the same ship that Darnell was using to sail to London. The Baroness has one of her goons disable the ship's engines while she disables the radio and makes the ship invisible using her invisible ray. She then uses her own radio to signal a German U-Boat. The Germans capture Darnell and shoot a torpedo at the now visible Gigantic.
Wonder Woman and Steve have, in the meantime, set out in Wonder Woman's Invisible Plane. They find the Gigantic and the U-Boat. Steve boards the U-Boat while Wonder Woman dives under water and stops the torpedo. She then uses her new lasso to make the German Commander order his troops to surrender, which he does. Not trusting U.S. authorities to keep the Commander and the Baroness under control, Wonder Woman promises to take them to a prison of her own choosing with the hope of reforming them.