Denny Swan, the Energy Superman, wants to become the one and only Superman by killing the original Superman. Clark refuses to give in to Denny’s demands and attempts to remind him of who he really is. Denny’s energy aura becomes more unstable by the minute and he resumes his attack until Batman, Wonder Woman and Supergirl arrive to help. Superman uses the opportunity to grab Denny and attempts to take him to the upper atmosphere, where he plans to use his solar flare to counter Denny’s unstable energy, but his power gives out before he can reach orbit.
Fortunately, help arrives in the form of the New Earth Superman, who takes them outside Earth’s orbit. The Prime Earth Superman, thanking his alternate self for his help, asks him to continue protecting Earth in his place, right before throwing him back to Earth. Then, he uses his solar flare just as Denny explodes. The plan works and both explosions cancel each other out. Denny is incinerated while Clark falls back to Earth. The New Earth Superman catches him before he hits the ground.
Unfortunately, Superman’s Kryptonite poisoning has already reached its final stage and the gathered heroes share their final moments with the Man of Steel. He thanks them for the friendship and love: he says goodbye to Lois and Lana, asks Supergirl to carry on his legacy, thanks Steel for having his back, Batman for being his comrade and friend, and Wonder Woman for everything. He lets himself go, and his body is reduced to dust, with only his cape remaining. The New Earth Superman takes his leave, but not before promising to stay in touch with the other heroes. Lois, Kara, Lana, Bruce, Diana and Steel mourn him.
Later, the world mourns the loss of Superman. During that time, Luthor has created a new armor based on Superman’s uniform and Lois has begun writing a new article: “Superman: A Hero’s Life.”