Having escaped death during the crash of his airship. Buck and his crew survive by using a strange suspended animation gas. Awakened 500 years later by scientists he finds the earth under the rule of gangsters like Killer Kane. The only chance is to seek help from another planet.

Escaping from earth Buck and his crew travel to Saturn. Having been followed by two of Killer Kane's ships, they are shot down over Saturn. Escaping the crash by using gravity belts they are pursued by Kane's men and captured by the forces of Saturn. Having gone to Saturn to get help against Kane, They find the people of Saturn less than helpful. Buck and his crew stand trial on Saturn, and escape back to Earth.

Buck delivers a war pact from Prince Tallen to Killer Kane.

AIR MARSHAL KRAGG orders the Kane Ship entering the "Hidden City", crushed in the outer gates, only to find the crew to be Buck, Wilma and Buddy, who used the ship to escape from Saturn. BUCK informs Kragg and Doctor Huer of Laska's treachery by inciting the Saturnians into believing the "Hidden City" people were revolutionaries plotting against benevolent "Killer Kane". BUCK and BUDDY gain entrance to Kane's private council chambers preventing Prince Tallen signing the treaty that pledged the Saturnians' support to Kane. CONVINCING TALLEN of Kane's brutality, Buck, Buddy and Tallen escape to an outer terrace.

BUCK ROGERS and Buddy Wade, in Kane outfits gain entrance to Kane's chambers in time to expose the brutal "Leader" and prevent Tallen signing the treaty. Escaping in the Killer's personal ship, Buck, Buddy and Tallen head for the "Hidden City", but are attacked en-route by Wilma Deering's "Hidden City" squadron, who mistake the for enemies in a Kane ship and follow it down to a landing. DISCOVERING their friends, the "Hidden City" Squadron head for home, expecting Buck, Buddy and Tallen to follow in the Kane ship. BUCK finds his rocket ports damaged and before repairs can be made they are attacked from the air by Kane's pursuit ships.

WILMA DEERING and the "Hidden City" squadron encounter the Kane Patrol that is bombing Buck, Buddy and Tallen from the air. Combating the Kane ships and forcing their retreat, Wilma lands and takes Buck, Buddy and Tallen to the "Hidden City", where Buddy, who has been seriously wounded, is removed to the hospital. PRINCE TALLEN pledges his people's support to Doctor Huer by signing the treaty entrusted to him . Unable to make radio contact to ratify the treaty, Buck, Tallen and Wilma fly to Saturn, only to discover Laska in a Kane ship has already arrived to prevent the alliance. BUCK decides to disable the Kane Space Ship, making escape of Laska and crew from Saturn impossible.

BUCK and Wilma arrive on Saturn with Prince Tallen, where they are trapped in a space ship by Laska to prevent their having the treaty ratified. LASKA, forcing lethal gas into the control cabin, renders Wilma, Tallen and Buck unconscious. TURNING Buck and Wilma over to Patten, his lieutenant, Laska by means of a ray filament inserted inside Tallen's helmet transforms him into a human robot. BUCK and Wilma escape their captors and rush into the Forum, to find Tallen in a hypnotic stupor condemning Buck and the "Hidden City" people. SIEZING Tallen bodily, using him as a shield, Buck and Wilma start toward the tunnel car.

AFTER crashing into the outer gate in their attempted escape by tunnel car, Buck and Wilma remove the filament from Prince Tallen's helmet, restoring his senses. CAPTAIN Laska and his forces, fleeing from the Saturnians, find one of their human robots in control of the primitive Zuggs. TAKING advantage of this situation, Laska commands the Robot to order the Zuggs revolt against all Saturnians. THE COUNCIL of the wise pledges support to Buck and the "Hidden City" people as Laska and the Zuggs march on the Forum.

CAPTAIN LASKA, Killer Kane's emissary, takes over the Saturnian Forum with the aid of the revolting Zuggs. BUCK ROGERS frees Wilma and Prince Tallen from prison and the three make their way into the Forum through a secret panel, to find Laska in full control. COVERING Laska, Buck removes the filament from the robot's amnesia helmet. The robot proves to be a former Hidden City soldier. FREED from Laska's influence, the robot orders the Zuggs to imprison Laska and return to their Saturnian rulers.

BUCK ROGERS and Wilma returning from Saturn encounter a Killer Kane Patrol Squadron which brings their space ship down in flames. The Kane soldiers land and take the unconscious Hidden City people prisoners. Refusing to divulge the secret of the camouflaged Hidden City gates to Killer Kane, Buck is ordered to the robot battalion. BUDDY WADE does not share the belief of the Hidden City people, that Buck and Wilma were killed in the crash, and with the help of Captain Rankin flies over Kane's city.

BUDDY WADE escapes from Kane's Council Chambers where he has gone in search of his friends Wilma Deering and Buck Rogers. MAKING his way along the palace terrace Buddy encounters Wilma and together enter the dynamo room, relieve Buck of his amnesia helmet, restoring him to consciousness.

ENTERING the control room, Buck and Marshall Kragg discover Carson, a Kane Lieutenant, operating the Hidden City gates. BEFORE Kragg can close the gates, two ships of Kane's squadron get through, but their crews are soon captured. BUCK and Buddy go to Saturn to enlist their Allies for a final drive against the outlaw forces of the earth.