All Star Superman

Dr. Leo Quintum and his team are exploring the Sun when they encounter danger from a genetically enhanced Lex Luthor clone. Superman intervenes and saves the team, but his body is overdosed with solar radiation, which grants him new powers but also begins to threaten his life.

Superman decides to reveal his secret identity to Lois Lane to spend his remaining days with her, after learning his body is slowly dying due to the overdose of solar radiation. He takes her to the Fortress of Solitude for this revelation.

During their visit, Lois's paranoia is heightened by Superman's indirect exposure to alien chemicals, leading her to attack him with a kryptonite laser. Superman, now immune to green kryptonite, manages to calm her down and reveals his special gift for her birthday.

Superman grants Lois superpowers for 24 hours, turning her into Superwoman. They stop a Subterranean attack in Metropolis just as Samson and Atlas arrive, with Samson revealing a theft involving Lois and an Ultra-Sphinx.

Superman and Lois, as Superwoman, answer to a crisis involving the Ultra-Sphinx's jewel theft and answer its unanswerable question to save Lois. Superman wins a double arm-wrestling match against Atlas and Samson, showcasing his strength.

Clark Kent visits Luthor for an interview at Stryker's Island, where Superman's energy inadvertently frees the Parasite, causing havoc. Clark stops him without revealing his identity, and Luthor reveals a secret tunnel for Clark's escape.

Luthor expresses no desire to escape as long as Superman dies before him. Clark escapes through a tunnel with the help of Nasthalthia, Luthor's niece, after Luthor tricks the guards into giving him super serum.

Superman learns that Solaris, a tyrant star computer, has tampered with Earth's sun by turning it blue, betraying Luthor. Superman engages Solaris in space, with his robots and Sun-Eater sacrificing themselves to weaken Solaris and allow Superman to destroy it.

Superman, severely weakened, returns to the Daily Planet to submit his article. He fights off Luthor when the villain tries to kill Lois, using a gravity gun intended to burn out Luthor's powers early. Superman succumbs to his injuries and enters the Sun as his body turns into energy.

Superman flies into the Sun, merging with its energy to save Earth for the last time. A memorial service is held a year later, though Lois believes he will return. Luthor, now enlightened, offers a formula to recreate Superman's genetic structure as a redemption.

Inside the Sun, Superman, now a solar entity, activates and begins creating machinery within the Sun, indicating his ongoing transformation and potential return, leaving behind his mortal form but ensuring his lasting influence on Earth.