An alien called Commander Calibax and his crew of space criminals have fled into Earth's space sector, prompting the Guardians of the Universe to call Hal Jordan into action as Earth's Green Lantern. The Green Lantern easily breaks open the alien's ship and fights it's crew. During the battle GL gets very cocky toward the crooks and bungles up capturing their leader when he is caught in a yellow gaseous cloud created by a smashed meteor. Chasing Calibax to Earth, Green Lantern loses him and decides to give up and wait for the crook to resurface.

When he is called by a group of small children he stops to give them autographs when he is approached by a man named Professor Cally, who tells the Emerald Gladiator that he may have the solution to the power rings inability to effect things that are yellow. Hal takes the man to dinner to learn about his secret and learns that Cally has invented a filtering device that allows the power ring to effect things that are yellow. Giving Hal a copy of the device, Hal is shocked to find that the device works and uses it a to fight a number of crimes, all successful. Thanking Cally, Hal goes to the Guardians of the Universe and tells them of the discovery. Impressed, the Guardians take note of the device's protection but advise Hal to return to Earth and test it out some more to make sure that there are no impurities or side effects.

Returning to Earth, Hal resumes his civilian identity and reports for work at the Evergreen Insurance Company. There his boss, Mr. Lawford, tells him to check the security of the Evergreen Hospital which has been caring for criminal Winkey Eiler who has been there since taking a slug, because there is fear that his gang may try to spring him or silence him before he can testify in court. Arriving at he hospital, Hal notices the gang breaking into the hospital via helicopter and changes into Green Lantern. While fighting the crooks, he finds that his power ring is acting strangely and has to exert additional will power just to make it function properly. He eventually stops the crooks as well as prevents their helicopter from crashing onto the street below.

Returning to his room Green Lantern tries to recharge his power ring and goes back out into action to try and figure out what caused his ring to malfunction. While he is patrolling the city, he spots another one of Calibax's ships and tries to attack it. His ring fails him once more and Green Lantern is seemingly slained by Calibax, who turns out to have been posing as Professor Cally, and used the filter to weaken the Emerald Guardian's power ring. Finding the Green Lantern's costume and power ring in the rubble, he claims them and leads his pirates to the Doremus home. They take the Doremus family hostage and decide to use their home as a staging ground for their plans. Hal, meanwhile has survived the attack and has borrowed the uniform and scooter of a post man so that he can get close to the Doremus home undetected. Over powering Calibax's men, recovering his costume, the Green Lantern overhears Calibax explain to Eve's father that the "filters" true function was to eventually render their power rings useless. Hal bursts into the room and is able to best Calibax in hand to hand combat, telling him that a Green Lantern's might comes from his skill, and not his power ring, strip him of the latter and he will always be able to defeat you with the former.

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