Superman delivers an acre of top soil to Ethiopia. A sirocco threatens to blow away the top soil, but Superman's quick actions save the majority of it. Lee Ann Layton, a member of the Peace Corps, casts doubt on Superman's ability to truly change Ethiopia for the better. Superman carries out his task to pepper the Ethiopian landscape with acres of top soil. The top soil is blasted out of Superman's hands. Miles away, Batman investigates the crash of an airplane, which was delivering food to Ethiopia. Seeing Superman flying overhead, Batman signals the Man of Steel to join his investigation.
A cursory glance with his microscopic vision reveals that a particle beam brought the plane down. Superman tasks Batman with enlisting the aid of Superman's nemesis, Lex Luthor. Batman tasks Superman with discovering how their unknown foe knows the schedules of the famine relief planes. Superman's investigation brings him into conflict with a trio of androids, which Superman destroys. Superman traces a broadcast signature to an alien craft, buried miles beneath Ethiopia. Superman confronts the Master, an alien that feeds off hopelessness and entropy.
Superman battles the Master, only to find himself teleported away, back to the surface. Batman storms Luthor's island base. Batman confronts Luthor. Batman convinces Luthor to use his plant growth formula to aid Ethiopia. Luthor only consents to prove his superiority over Superman. Batman, and Luthor, rendezvous with Superman. Suddenly their surroundings are plunged into pitch, as the entire planet is encased in a sphere of total darkness. With the Earth completely cut off from the light of the Sun, all life on Earth is in jeopardy.
Luthor locates the Master's ship, just outside of a refugee camp for famine victims. Luthor is visibly shaken by his encounter with the starving children. Luthor tasks Batman with evacuating the camp. Luthor teams up with Superman to confront the Master. The Master teleports Superman into another dimension. Luthor attacks the Master, who grows stronger feeding off Luthor's despair. Layton chastises the Batman for placing the camp in danger. Batman races to the Master's ship to render assistance. Superman flies faster than the speed of light to escape the Master's dimension of abject darkness.
Playing the instrument lodged in his chest, the Master releases four fireballs, each threatening a different city. Superman is forced to abandon Luthor, to deal with the new threat. Superman dissipates the fireballs. Luthor continues his desperate battle against the Master. Batman joins the fight. Luthor projects a force field around the Master's destructive instrument, preventing the Master from playing it. Nonetheless, the Master closes on Luthor, intent on crushing the life from him with his bare hands. Superman intervenes, and beats the Master into submission.
Superman wrenches the instrument from the Master's chest, then hurls the Master into the dimension of darkness. With the threat of the Master ended, Superman works with Luthor to end the famine in Ethiopia. Luthor's plant growth formula, however, fails. What worked on Luthor's world, Lexor, is incompatible with the soil composition of Earth. Layton explains that it took man years to turn Ethiopia into a desert, and a single afternoon of super-heroic efforts was never going to restore it. Layton states that it will take a concerted effort, on the part of the entire world, to save the African continent. As Batman, Luthor, and Superman depart, Layton allows herself to feel hope for the future.