The premise of "Crisis on Two Earths" is borrowed from the 1999 Grant Morrison JLA: Earth 2 story, where a heroic Lex Luthor from an alternate universe coming to the Justice League for help against the Crime Syndicate, but it is not an adaptation of that story. The film is the seventh in the line of the DC Universe OriginalAnimated Movies line released by Warner Premiere and Warner Bros. Animation.
In the Justice League: Crisis on Two Earths animated, a good (For a change) Lex Luthor arrives from an alternate DC universe to recruit our Justice League to help save his World from a super-team called Crime Syndicate. A super-team with virtually identical super powers to that of the Justice League. What ensues is a epic spectacular battle of good versus evil in a super war that threatens both Earths and thanks to Owlman, he puts a diabolical plan to work that puts the balance of all existence in peril.