A year after the events of World's Finest, Batman finds out that moments before he was arrested, Lex Luthor had communicated with an alien from the Kryptonian ship. He informs Clark and Diana about this. Diana later reveals that the alien he talked to was Steppenwolf , an alien from a far away galaxy who previously tried unsuccessfully to annexe Earth millions of years ago with his army. Steppenwolf is coming back this time on orders of his nephew and king of Apokalips,Darkseid as an attempt to show his worth to the ruler. However Steppenwolf has more expansive ideas about this venture. The trio decide to defend the Earth this time with the help of other metahumans , whereas the time is short for the group to form.
