An alien spacecraft lands in Arizona and starts making lots and LOTS of bug-like machines from surrounding matter. The entire JLU bands together to stop it. Martian Manhunter fires the JLU satellite's energy gun for the first time to build a trench, but it only buys them a little time. They turn to The Atom for help.
Wonder Woman, Superman, and Doctor Light battle their way in through the hoard to deliver Atom to the center of the threat while others hold the line to protect the nearby towns.
This episode was written by Warren Ellis.