The entire planet is in mourning as a procession of heroes carrying the green faced body of Superman, who has recently passed away, go by a number of mourners into the Hall of Justice. Firestorm, who apparently was with Superman during the terrible accident that claimed the hero's life, is overwhelmed with grief and can not be consoled.
A short time later, the heroes, with Superman's casket, leave the Hall in a spaceship and head out of Earth's orbit. As they do, they pass a number of alien ships gathered to pay their respects.
The heroes arrive at their destination and after final words from Batman, Superman's casket is launched into the sun. A disconsolate Firestorm, blaming himself for Superman's demise, leaves the ship and heads back to Earth alone.
As this goes on, Desaad and Kalibak, observing from Apokolips, revel in what they have just seen. However, Darkseid says it could be a trap and wants absolute proof before making any move.
On Earth, Firestorm continues to wallow in self-pity before encountering a number of Darkseid's robots, who have been transported there via one of Darkseid's star gates. Firestorm is captured by parademons, who were hiding out of sight, and is dragged away by them in an energy net.
Wonder Woman, Green Lantern and Cyborg fly to Superman's Fortress of Solitude to put his affairs in order.
Firestorm is immobilized by Desaad's device and a scan of his mind reveals what happened to Superman on the fatal day. Firestorm's mind reveals that he and Superman stopped on the planet Geminine so Superman could gather crystals he can gather for use in his researching a cure for kryptonite. Superman asked Firestorm to wait by the ship before he flies off to gather the samples. However, Firestorm, intrigued by the colorful appearance of the surroundings, went off to explore on his own. Superman was collecting samples from the base of a cliff when a rock slide exposes a large vein of kryptonite deadly to Superman. Superman called for help over a transmitter but before Firestorm could respond, he was grabbed by a giant plant creature and dragged towards it. After struggling for a brief time, Firestorm managed to free himself but when he found Superman, the hero had turned green from Kryptonite poisoning and was lifeless. Satisfied that Superman is truly dead, Darkseid prepares to take advantage of the absence of the great hero
Green Lantern uses his ring to raise the giant key necessary to open the Fortress door but just after the heroes enter the structure, they are pinned by a powerful energy field. Cyborg manages to destroy the projector with a well placed sonic blast and moments later, the heroes see a figure walk towards them that they mistake for Superman for a moment or two. However, it is a robot built by Superman in his liking that are programmed to be caretakers for the Fortress while he is away.
The robot leads the trio to an area where Superman had built a Kryptonian Rejuvenator machine, designed to cure effects of severe kryptonite poisoning. The robot also mentions that Superman could have put himself in an Kryptonian trance, which is designed to slow down the process of kryptonite poisoning. Seeing a video of Superman practicing such a trance in the past, Batman, noticing the hand positions are the same as what Superman was found like, states Superman may still be alive.
Back at the Hall of Justice, the heroes present see Firestorm approaching on a monitor but is not signaling for the force field to be dropped to allow him entrance. Figuring Firestorm's grief is clouding his thinking, Hawkman drops the force field and moments later, star gates appear, Darkseid and Kalibak emerge and Darkseid knocks out the gathered heroes with his Omega beams. A moment later, Firestorm lands and reveals itself to be a parademon disguised as Firestorm. With the Hall of Justice secure, Darkseid contacts Desaad and tells him the invasion of Earth is about to begin. After Desaad leaves, Firestorm breaks free and heads to Earth to warn his friends.
A short time later, as the heroes prepare to leave the Fortress with the Rejuvenator, they see a large wave of robot drones heading their way as well as Firestorm. Firestorm and the heroes managed to fly off in the ship and head for the sun and the location of Superman's body. Once there, with Firestorm enhancing their heat shields, they manage to retrieve Superman and leave the area with Superman hooked up to the Rejuvenator.
Back on Earth, the citizens of Metropolis panic as they see a Darkseid ship manned by Desaad. Moments later, Desaad appears in the Hall via a star gate and hands Darkseid a device that allows him to open multiple star gates in space around Earth. However, before Darkseid can order his invasion fleet to attack, he sees his ship destroyed outside followed by Superman crashing through the roof. After firing his Omega Beams at Superman, Darkseid and his men go back to Apokolips via a star gate. Firestorm is thankful for Superman's return even as Superman says the story behind his return is a long one and Batman, seeing the star gates around Earth disappear, states they have plenty of time.