What's 50-feet-tall, nearly indestructible, and on a rampage through New York City? Iron Man calls it "Ultimo"... but to the members of Power Pack, it's just another super-jerk trying to ruin their day off! And while our young heroes join forces with everyone's favorite armored Avenger to bring down this mega-sized metallic monstrosity, are they missing something far more sinister going on behind the scenes? Does the action ever end?!? Not for Marvel's youngest heroes!