Here is the sypnosis as I have yet to fully write out the Screen play for the movie that I will hope to get on soon.
Lex Luthor is announced the President of the USA. He promises to build a new and better America and with LexCorp finding brand new oil in the Mexican Gulf that will fund the rebuilding process. However, one of his digging teams hits an alien ship that Lex believes was left by Darkseid. Superman identifies writing on the ship as Kryptonian and warns against opening the ship. Lex doesn't listen however and has the ship brough to Metropolis and opened, releasing Doomsday, an unstoppable monster bread to destroy life. Some of the Justice League confront Doomsday whilst Superman is with Lois in Afghanistan covering a story. When the news breaks, Superman confronts the monster who has already defeated the Justice League and the two battle till death, with the ensuing battle destroying half of Metropolis and killing both titans. Superman is given an honoury funeral buried in Metropolis with the planet unaware that Brainiac, who is still residing in LexCorp hardware, has rebooted himself and is constructing a new body ready to take earth's knowledge and then destroy it.
Please comment on what you think. I tried to take elements from the Comic storyline and intertwine it with my own storyline set from through the movie series.