Between Friend And Foe! Superman is relieved from monitor duty aboard the JLA Satellite by Green Lantern. In the middle of his monitor duty he is seemingly contacted by fellow Green Lantern Archon Z'Gmora of the Cygnus system. His fellow Lantern asks for assistance telling him that he is trapped in another dimension and his power ring has run out of power, his only means of communicating with Hal is via his telepathy. With communication broken, Green Lantern recharges his ring and uses it to travel to this other dimension. However, he learns that he has fallen for a trap.
Archon is already dead and he had been replaced by a creature called N'Gom. The creature seemingly slays Green Lantern, takes his form and removes his power ring. It gloats aloud about how it was a singular entity until one day an energy tendril from a green sun split it into two distinct beings. The two would war with each other and find that they were evenly matched in their present forms. Since then the two have sought out more powerful beings to replicate in order to destroy each other. It had trapped Archon hoping to steal his power ring, but was forced to contact Hal Jordan when it proved to be powerless. Now with Hal's Power Ring and Power Battery in his possession, the N'Gom is confident that it can destroy its doppelganger.
However, Hal is not really dead, at the last moment he had used his Power Ring to separate his soul from his body. Not in an incorporeal form he wonders how he can stop this menace. Getting close enough to his ring to effect it with is will power, Green Lantern pulls Superman from Metropolis before the Man of Steel can save a man who fell from the top of a building under construction. There Superman appears before the N'gom posing as Green Lantern, and the Man of Steel believes it to be his friend. Worried that the creature will slay his ally, Hal re-enters his body and blows the N'Gom's cover. Leading to a clash between the two. Superman manages to fend off the Power Rings energy by wrapping his cape around his arm and using the yellow Superman emblem to deflect the any attacks.
Compensating for this the N'Gom uses the Power Ring to create a massive chunk of Green Kryptonite that threatens to kill the Man of Steel. Green Lantern then grabs a rock and strikes his enemy in the back of the head with it, breaking his concentration and sending the Kryptonite disappear. Superman resumes his fight with the N'Gom, and beats it senseless, knocking it out causes it to resume its natural form.
Superman hands Green Lantern back his Power Ring and he uses it to contain the N'Gom so that he cannot threaten anyone again. When Superman laments over the construction worker falling to his death, Green Lantern points out that time moves much slower in this dimension and they both return to Metropolis with enough time to save the falling man.