Superman and Batman team up with the league to take down the Legion of Super-Villains and restore the timeline. As the other heroes fall Superman is left to confront Cosmic King while Batman takes on Ra’s. Superman defeats King and sacrifices himself to save Bruce form being stabbed by Ra’s sword.
Enraged at the seeming death of Kal, Batman decapitates Ra’s and the remaining villains realise that they need to return to the time stream. But removing the sword, Superman recovers and together the two heroes take them all down.
They hand the villains over to the Legion of Super-Heroes in the 31st Century and the timeline restores itself to normal. However, Kal and Bruce retain their memories of all the horrific things they had done and a guilt ridden Superman asks Diana to see him. He rejoices in seeing her so alive and vibrant and tells her that he treasures her friendship and no mater their differences, that will never change.