Not only does the crystal grow violently as expected, but it also generates an EMP pulse which temporarily knocks out the power grid of most of Metropolis. In the next chapter of the story, Lex Luthor explains to his goons at the former Vanderworth estate how Kryptonian technology was based around the growth and expansion of Sunstone Crystals, giving them a demonstration by placing a minute sample of Sunstone in the water-filled area of a miniature model train set. Then, Superman dives through the giant Metallo's heart and tackles the real Metallo out of it, knocking him out in the process. Metallo then launches a large missile to raze a Metropolis skyscraper, which Superman intercepts. When Superman recovers, he chases Metallo down to a square within the city and attacks him using the environment. In his first few reunion scuffles with Superman, Metallo gets away when Superman gets the upper hand, but in their final encounter, Metallo knocks Superman out with his Kryptonite heart and transforms into a giant mechanical monstrosity. Metallo and his legions of robot minions and AI-piloted hovercraft rampage for some time throughout Metropolis, putting innocent lives in danger to bring Superman out. Meanwhile, Metallo, the villainous cyborg with the Kryptonite heart, has decided to mark Superman's public return by using his mechanokinesis to create an army of robots powerful enough to combat even his invincible old foe. These challenges include saving kittens, racing Mxyzptlk across the skyline at the speed of sound, and being magically transformed into Bizarro to destroy as much of Metropolis as possible before the spell wears off. Mxyzptlk, who tasks Superman with completing several challenges of different kinds for him as an alternative to the usual "Kltpzyxm" routine. Back near the Daily Planet, Superman re-acquaints himself with his trimonthly extradimensional imp visitor, Mr. Luthor then absconds with Sunstone from the Fortress and returns to his base, the acquired former Vanderworth estate. Setting into motion his next plan, Lex Luthor, accompanied by his hench-woman Kitty Kowalski, infiltrates the Fortress of Solitude during Superman's absence and learns about the unique properties of the Sunstone Crystals from the holographic recording of Jor-El. Even still, there are some who are dismayed not because Superman did not return soon enough but rather because he returned at all: Superman's rogues' gallery. Clark is saddened and slightly dismayed at Jimmy Olsen's news that Lois Lane grew tired of waiting for Superman's return and decided to start up a new relationship with Perry White's son Richard instead, though Jimmy's personal suspicion is that Lois never fully gave up her affections for the Man of Tomorrow. Superman then returns to Earth and resumes his day job at the Daily Planet in his Clark Kent identity. When Superman wins both fights, Mongul enters the ring himself to humble the Kryptonian, but even he falls before the might of Superman, who then easily escapes from Warworld.
Intrigued by the existence of the Last Son of Krypton, Mongul brings Superman to his gladiatorial artificial planet Warworld and forces him to battle with his powerful extraterrestrial champions, Plahtune and Overkhast, to compete with them for audience favor. Unfortunately, Superman discovers that Krypton was indeed destroyed, and the Man of Steel is captured by the slaver ships of the alien despot Mongul on the return trip to Earth. In the meantime, Lois Lane grows upset at Superman's decision to leave Earth, and Lex Luthor is freed from prison on appeal. Afterwards, theories by astronomers that Krypton in fact never exploded convince Superman to embark on a search to the other side of the universe, in the hopes that he might find his home-world intact and thriving. In the process of thwarting Lex Luthor's plans, Superman manages to get him convicted and given a life sentence in prison. After the crisis is averted, the events of the years that follow are reviewed by a montage of Daily Planet newspapers. Clark Kent, seeing this before the disaster strikes with his telescopic vision, turns into Superman and smashes the meteorites before they can hit the city with his array of super-powers and the additional guidance of Jor-El's holographic recordings and Professor Emil Hamilton of S.T.A.R. The game opens with a rain of meteorites threatening Metropolis with destruction.