Recap / Justice League Unlimited S 1 E 10 Dark Heart

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:

  • A.I. Is a Crapshoot: Subverted. The Dark Heart did what it was programmed to do: replicate itself, and consume matter until it devours entire planets. It's only because the civilization, were as with the case with such destructive technology, were destroyed by their own creation, that it doesn't realise that the war that they were designed for is long over.
  • Abusive Precursors: The Dark Heart was part of a series of war machines created for a conflict, initially assumed to be interplanetary, but was more likely interstellar (at the very least), that would eventually eradicate planets of the opposing side, and move on to the next. The conflict occurred around 50,000 years ago and by then, it had likely destroyed the civilization that created them - one of the probes arrivals on Earth, was more coincidental than deliberate.
  • Apocalypse How: Class X, at the very least. Perhaps even Class X-2 going by what the Atom said about it.
  • BFG: This is the first time that the League break out the Binary Fusion Generator, described as packing enough force as a nuclear warhead, its used for the first time to slow down the advance of the nanomachine robots. The bad news: It uses the entire power of the Watchtower, which reboots its system in an hour after usage. Even worse news: It did very little to slow them down.
  • Hope Spot: 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.
  • Godzilla Threshold: The Dark Heart pushed Martian Manhunter to declare a threat level of "Omega": Meaning sending every single superhero in the Justice League onsite to deal with it. They barely contained it, and given the amount of Badass Normals on the team, they were very lucky not to have received fatalities. To put it in perspective: only the threats of Amazo and Darkseid later would prompt a similar response.
  • Grey Goo: A particularly scary version of this trope, and one that isn't just limited to one planet in the scale of threat.
  • Hopeless War: No matter how many robots the League and the Army destroy, more would instantly take their place.
  • The Juggernaut: The Dark Heart was practically unstoppable. Even the full might of the entire Justice League could barely slow it down. Only the Atom shutting down the central core, by giving it the equivalent of a heart attack, shut it down.
  • Mook Maker: The namomachine blob releases hundreds of separate machine creatures/drones to consume everything in sight, even the surface. The more the drones are destroyed, the more they the creatures/drones, this time larger and stronger are released from the hub.
  • Nanomachines
  • This Looks Like a Job for Aquaman: The Atom, who in an earlier episode was described as the League's weakest member by Luthor, is the right man for the task of stopping the Dark Heart; having an expertise on nanotechnology and his ability to shrink into microscopic size, he found the Dark Heart's weakness, damaged its 'central power core', and shut it down - saving the world.
  • Too Dumb to Live: 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..."
  • Victoria's Secret Compartment: Wonder Woman placed a miniaturized Atom down her cleavage so she could use both her hands to fight the robots.
  • Wham Line: When Superman retrieves The Atom, and talks to Batman over the commlink, having bought time with their space BFG to create a trench around the nanomachines:
    Superman: We should be arriving soon. How's the trench holding up?
    Batman: What trench?
    (Complete with Wham Shot of nanomachine robots advancing having already reached ground level)
http://tvtropes.org/pmwiki/pmwiki.php/Recap/JusticeLeagueUnlimitedS1E10DarkHeart