A rock-climbing couple unfortunately discover a huge pulsating blob of nanomachines that dropped in from space, which begins to rapidly produce robotic monsters bent on consuming everything and replicating itself until there's nothing left. Practically all of the Justice League is called in to stop the threat, but the battle seemed hopeless. Only The Atom has any chance of stopping the nanomachine nightmare for good.

!!This episode includes examples of:

* HopeSpot: Martian Manhunter uses the Watchtower's satellite cannon to dig a deep trench around the nanomachine blob in an attempt to at least slow it down. Unfortunately, it somehow managed to RESTORE the trench to solid ground again, like it was never there.
* HopelessWar: No matter how many robots the League and the Army destroy, more would instantly take their place.
* TooDumbToLive: General Eiling takes most of the killer robots back for study once the battle was won, saying that it "may prove useful as it almost defeated the Justice League". Atom summed it up well.
--> Atom: "Show him something that destroyed its creators and everything around it, and he wants to play with it..."
* VictoriasSecretCompartment: Wonder Woman placed a miniaturized Atom down her cleavage so she could use both her hands to fight the robots.