The Justice League is accidentally transported to a parallel world and find the Justice Guild of America, comic book characters in the Justice League's world. While battling super villains in this other dimension, they discover that the world is just an elaborate illusion.

Exposed as a criminal, sentenced to prison, and terminally ill due to long term kryptonite exposure, Lex Luthor escapes and assembles a supervillain team consisting of Cheetah, The Shade, Solomon Grundy, Star Sapphire, Copperhead, and Ultra-Humanite to take on the Justice League, calling themselves the Injustice Gang. The Joker also becomes part of the team, but on his own invitation. However, even with their combined power, this gang proves no match for Batman's wiles.