The Raven, a villain whose hideout is hidden in a mountain near Good Haven, attacks the city with his "plastic blaster" gun. It seals its victims in plastic. The Mighty Heroes respond. Eventually, the Raven (aided by his flock of villainous birds) gets the upper hand, sealing Tornado Man, Rope Man, Strong Man and Cuckoo Man in plastic. Diaper Man sneaks into the Raven's hideout and in the fight that follows, the other heroes are freed. After disposing of the Raven's flock of birds, the villain is about to strike again. However, Diaper Man flings his bottle, jamming the barrel of the plastic blaster. It is now the Raven who's sealed up.
The Junker, whose base of operations is beneath a junk yard in Good Haven, creates robots that "eat" metal. The Junker's robots consume cars, bridges and other structures. The Mighty Heroes attempt to contain the damage and eventually follow the robots back to the Junker's lair. But the villain traps the heroes inside a metal container, which he then crushes. Now, the Junker sicks his robots, saying they're free to consumer a "hero sandwich." But the heroes prevail, destroying the robots and capturing the Junker.
The Monsterizer and his gang of monsters kidnap prominent citizens of Good Haven, including the Mayor and Police Chief. They are then transformed into monsters by a device, creating more lackeys for the Monsterizer. The Mighty Heroes respond to a call for help. They attempt to reason with the Mayor and Police Chief, but instead get captured. The heroes are put into the Monsterizer's machine, with Rope Man used to tie them up. The heroes can't escape without snapping Rope Man in two. Diaper Man uses his milk bottle to prevent the Monsterizer from activating the device, giving the heroes enough time to escape. They eventually overpower the Monsterizer and change the Mayor and Police Chief into their old selves.
The evil Drifter moves in to take over the town of Good Haven with his helper (who looks like Frankenstein's monster). Overlooking the town, the Drifter unveils a sinister new weapon: an anti-gravity gun so powerful that it lifts the entire town 6,000 feet in the air. He agrees to let the town back down again for $10 million. A call goes out for the Mighty Heroes...