The babies and Angelica are watching the Mega Hyper Heroes, a Captain Planet type show. Two of the heroes are being chased by Metalitron, a giant robot that is firing lasers at them. Johnny states that if the others were here they could put their rings together and become the Mega Hyper Heroes. They run into a cave and are reunited with the other two who were off saving the rainforests.They put their rings together and become the Mega Hyper Heroes! Changeling, with the power to change into any animal, Flamo, with the ability to ignite himself with fire, Miss Invisible, with the ability to turn invisible, and the Bolt, with the strength of two really strong men.
They prepare to battle Metalitron but she has already found them. She punches Changeling into a wall causing him to turn into a cobra which she uses to tie up the others. The announcer asks if this is the end for the heroes and to tune in next week to find out.
Angelica states that Metalitron is her favorite character. Tommy states that she is evil and takes what isn't hers. Angelica does the same and snatches the babies Mega Hyper Hero action figures and runs off. Tommy wants to get them back, but the others don't think that they can. Tommy says that the real Mega Hyper Heroes could and they can become them. The others wonder how since they don't have super powers, muscles, a T.V. show, and most importantly the magic rings. However, Tommy says that they do have their teething rings. Putting them together they become the Mega Diaper Babies.
Tommy becomes Changing Baby capable of turning into animals, Phil becomes Spitball Boy, who can shoot out machine gun like spitballs from a spitball gun, Lil becomes Dotted Line Girl who is a dotted line, and Chuckie becomes Stinky who smells as strong as two babies. Chuckie however doesn't want to be Stinky.
The babies take off towards Angelicatron's evil lair to rescue the heroes. Angelicatron is watching on her T.V and orders Cynthatron to unleash her secret weapon. As the babies are nearing Angelicatron shows up and unleashes the Robo-Buster,a deadly robot. Changing Baby becomes an octopus and attempts to fight it, but he is no match. Spitball Boy then unleashes a barrage of spitballs that have no effect until he runs out. Dotted Line girl steps up to help and manages to deactivate it.
It's revealed that the Robo-Buster was mearly a vaccum cleaner and Lil mearly tripped the switch. Chuckie wants to play something else, but Tommy says they got to save the heroes and they head on.
They arrive at Angelicatrons mountain hideout (which is the stairs in the real world), Changing Baby turns into a spider and they start climbing up. Angelicatron unleashes her army of flying dummi bears at the babies. Spitball Boy attempts to hold them off but his spitballs have no effect so they are forced to retreat. In the real world it's revealed that Angelica is mearly tossing stuffed animals at them.
Chuckie again wants to play something else. Angered Tommy states that the Mega Hyper Heroes never gave up and neither should they. Phil and Lil agree to go on, relucently Chuckie agrees as well but asks why he has to be Stinky.
Angelicatron meanwhile has the Mega Hyper Heroes trapped in an anti-energy forcefold. Changeling says that she'll never get away with this. Angelicatron tells him to be quiet even though she's talking to a doll.
The babies are wondering how to get past Angelicatron's robot guards. Dotted Line girl volunteers to fly up in her ship. She gets past the guards and just as she is about to reach the heroes Angelicatron stops her. Dotted Line Girl wonders how she could see her when she's just a dotted line. Angelicatron points out that any idiot can see a dotted line. All a sudden Changing Baby as a rhino smashes through the wall with the others behind him. Reunited they state that they are The Mega Diaper Babies!
Unimpressed, Angelicatron reveals her ability and unleashes various weapons from her body. Dotted Line Girl attemps to battle her with her ship, but Angelicatron hurls it into a wall then destroys it with a laser. Spitball Boy then fires three spitballs at her, but she vaporizes them with another laser. Changing Baby turns into a giant bear, but she easily knocks him aside. Just as she is about to finish them off she smells something horrible. It's Stinky. He unleashes his horrible smell which makes Angelicatron unable to breathe and blow up. (which is ironic since a robot shouldn't need to breathe or need to smell)
Wiith her defeated the babies free the heroes. Changeling thanks the babies, but Changing Baby tells him there's no time for that and that they have to go save the oxygon. Miss Invisible agrees and tells him they have to leave. Changeling turns into an eagle and takes off with Flamo holding on while Miss Invisible and the Bolt take off in her ship. They say farewell to the babies as they head off to save the oxygen.
The announcer from the show then states that thanks to a little help from the babies the day is once again saved thanks to the Mega Hyper Hereos.
Meanwhile a now massive Angelicatron stands over Tommy's house and laughs manically.