James Gunn was recently on The Howard Stern Show and dropped a little nugget of info pertaining to the plot of his Superman sequel, Man of Tomorrow...
“It is a story about Lex Luthor and Superman having to work together to a certain degree against a much, much bigger threat,” he said. “And it’s more complicated than that. It’s as much a Lex movie as it is a Superman movie. I relate to the character of Lex, sadly.”
Source: The Hollywood Reporter