The plot of Young Justice: Outsiders has come to center around a cosmic concept known as the Anti-Life Equation. But what is this mysterious force and why does Darkseid, the ruler of Apokolips and leader of the evil New Gods, want it so badly?
First mentioned in Young Justice in season 3, episode 7, "Evolution", the Anti-Life Equation is the ultimate goal of Darkseid's universe-expanding conquest. The quest for the Anti-Life Equation brought Darkseid and his forces to Earth, where he battled with Vandal Savage and his metahuman children hundreds of years before the modern age. A truce was reached, however, when Darkseid's advisor and chief torturer, DeSaad, suggested that Earth's metahumans might be invaluable in calculating the Anti-Life Equation. Since that time, Darkseid and Savage have worked together in a secret alliance, with the metahuman trafficking operations overseen by Savage providing Darkseid and his followers with more subjects to study as well as more shock-troops for his army.
The search for the Anti-Life Equation the made a sudden leap forward in Young Justice, season 3, episode 21, "Unknown Factors", which suggested that Halo held the key to the Anti-Life Equation. This was confirmed one episode later in "Antisocial Pathologies", when Granny Goodness was able to use Halo's powers in conjunction with an inter-dimensional torture chamber called the Ghost Dimension to break the will of Dr. Helga Jace and force her to reveal her crimes to Terra and Geo-Force, whom she had come to regard as her own children after she forcibly triggered their metagenes. Through this, Granny was able to create a mathematical proof for the Anti-Life Equation: Life minus Free Will equals Anti-Life.
The high concept of a mathematical equation that can be used as a form of mind control was one of many ideas Jack Kirby introduced into his Fourth World line of comics. The idea of the Anti-Life Equation first appeared in The Forever People #5 in 1971. Though never given an exact definition, the comic defined the Anti-Life Equation and its horrible power by saying that "if someone possesses absolute control over you, you're not really alive."
With that idea in mind, other writers who followed Kirby and made use of his characters in their own stories came up with their own ideas as to just how the Anti-Life Equation worked and what forces might compose it. For instance, one story in Alan Moore's run on Swamp Thing affirmed that Love was a part of the Anti-Life Equation, if only through its absence. Regardless of the details, most writers have treated the Anti-Life Equation as a power that allows those who posses it to crush the wills of other people, by convincing them that life is meaningless and without existence without hope.
Such power in the hands of a despotic deity like Darkseid of the New Gods would make conquest on a galactic level all too easy. With Granny Goodness now in possession of Halo as of Young Justice, season 3, episode 23, "Terminus", the secrets of the Anti-Life Equation are now effectively in Darkseid's grasp. This leaves the heroes of Earth facing an up-hill battle, as The Team embarks on a desperate mission to save Halo from the forces of Apokolips.