The report is extremely specific, and if correct it means the film will be based on three issues of Justice League Of America. The issues are 183-185, all released in 1980. The story of those issues is certainly of the high-stakes this film needs. Summing it up as basically as possible, it involves Darkseid planning the destruction of Earth by blasting it with a ray in order to move his planet, Apokolips, into the Earth’s place.
For a film of this magnitude, it was assumed the crisis would have to be bigger than just affecting Gotham City or Metropolis,