An unusually heavy smog has settled over much of the East Coast. Superman finds himself responding to several smog related emergencies. After personally transporting an elderly man, with emphysema, to a hospital, Superman assists the woefully shorthanded fire department, with putting out a building fire. Superman closes out his rescue operations for the day, so that he can go on the air, in his guise as reporter Clark Kent, to cover the smog alert. In Star City, the Green Arrow is also contending with the oppressive smog. The simple act of taking down three robbers actually leaves the Green Arrow winded. The Green Arrow looks to the Star City branch of the National Weather service for answers. The Green Arrow learns that the smog is covering over half of the United States, yet the conditions to create a phenomena of such magnitude just do not exist. Whatever is creating the smog, and keeping it from dissipating, isn't natural. From the roof of the Daily Planet building, Superman spies trouble brewing in the skies over Star City. Jimmy Olsen asks the Man of Steel to carry him along, so that he might cover the story for the news. Rather than waste time arguing with Olsen, Superman complies. Zeroing in on a freak electrical storm, Superman drops Olsen off, to combat the storm unencumbered. Superman blocks an enormous bolt of lightning with his own invulnerable body. Surprisingly, the bolt is powerful enough to stagger the Man of Steel. Olsen takes pictures of Superman's struggles. The Black Canary and the Green Arrow encounter Olsen on the street. The Green Arrow fires a flare arrow to get Superman's attention.
Superman has discovered that the energy storm has been heating the atmosphere, creating an inversion layer that has trapped the air pollution above them. The energy has been drawn to the Earth, and Superman has already traced it to it's source. Superman carries the Black Canary, the Green Arrow, and Olsen to the Rocky Mountains. Suddenly, they are illuminated by spotlights, as soldiers surround them. After a demonstration of his super-powers proves he's really Superman, the Man of Steel, and the others, are invited, by Doctor Titus Selinger, into the "Z" Project Research Center. Selinger represents Zeta Industries, a corporation dedicated to finding new sources of energy from outside the solar system. The energy fueling the storm was discovered by Zeta Industries' scientists. Though they had no real way of controlling the so-called "Z" Energy, they tapped into it anyway. Selinger believes the smog to be a necessary by-product of their research. After all, though it may take several years, their research could yield an unlimited source of free, clean energy for all mankind. The Green Arrow furiously rails against Selinger for poisoning the atmosphere, then storms off. Superman stresses the need for Selinger to shut down his research project into "Z" energy. As Superman, the Black Canary, and Olsen prepare to depart, they suddenly became aware of the Green Arrow's absence. Taking matters into his own hands, the Green Arrow trips an alarm before he can shut down Selinger's machines.
The Green Arrow runs afoul of Selinger's security forces, fighting a running battle throughout the facility. Despite his best efforts, the Green Arrow is subdued. Stray gunfire hits a key control mechanism for gathering and storing the "Z" energy. The resultant release of "Z" energy into the atmosphere, where it bonds with the smog, inexplicably forms an enormous creature comprised of "Z" energy and smog. Superman battles against the creature, to no avail, as it makes it way towards Denver, Colorado. Left alone, while the research scientists initiate emergency protocols, the Green Arrow slips his bonds. Very quickly, the Green Arrow cobbles together a makeshift bow and arrows, out of industrial materials. So armed, the Emerald Archer once more engages Selinger's security forces. Unable to defeat the creature on Earth, Superman travels several billion light years into space, to the source of the "Z" energy. Superman uses his heat vision to trigger a super-nova in a nearby sun. The resultant explosion pushes the "Z" energy source off by a few degrees, to a point where it is no longer accessible from Earth. With the Green Arrow holding the security forces at bay, Superman destroys the "Z" energy collector, causing the energy creature to dissipate. Selinger is furious. Superman informs Selinger that, in a hundred years, the Earth will be in position to draw on the "Z" energy source again. Perhaps in that time, mankind will be more readily able to harness it. Selinger takes no comfort in Superman's words.