Plot

The Earth Defense Directorate faces a crisis when nearly everyone becomes sick after eating poisoned food. An attempt is made to create an antidote but the plan is thwarted when the laboratory is sabotaged and an assassin positions his weapon at Dr. Huer. Buck Rogers, Wilma Deering and Major Duke Danton travel to the planet Vistula where the poisoned food was exported from and they find a world engaged in slave labor. Then they discover that a fanatical religious leader and slave trader named Kaleel poisons Earth's food supply in order to weaken their defenses. Meanwhile, Kaleel is secretly planning to conquer Earth from his mountain fortress while their defenses are incapacitated.—Woodyanders

Buck Rogers and Colonel Wilma Deering are returning to Earth, when they see a fighter being attacked by a pirate and Buck Rogers helps him. However, it was part of the training of cadet Regis Saroyan and his trainer and Wilma's friend, Major Duke Danton, has a friction with Buck Rogers. Regis is sick and soon Dr. Elias Huer tells them that most of the Earthlings are sick after eating poisoned food discs. Dr. Mallory and the computer Carl are researching an antidote, but Carl is blown-up by his assistant Stella Warden that flees. Now the Earth Defense Directorate is weak with a few fighters and sends Buck Rogers, Colonel Deering, Major Duke Danton and Major Fields to the planet Vistula, ruled by Governor Saroyan and where the food is processed, to investigate what has happened. They learn that Saroyan uses slavery to produce the food and find that the slave trader Kaleel is the leader of the slaves. Further, Kaleel has weakened the defense forces since he intends to conquer Earth using the expertise of the rogue strategist Galen.—Claudio Carvalho, Rio de Janeiro, Brazil