Thanks to the Muscle League, peace has returned to Earth...but for how long? Vance McMadd, chairman of the Justice Federation, believes that eternal vigilance is the price of liberty. But Kid Muscle and his friends believe in kicking back and partying. Dismayed by their lazy attitudes, McMadd has sent four new Hercules Factory graduates, a group known as Generation Ex, to challenge the "Super Slackers."

Now Kid Muscle, Terry Kenyon, Dik Dik Van Dik and Wally Tusket are facing off against newcomers Jaeger, Hydrazoa, Scarface and Road Rage. Only one team will be allowed to remain on Earth to defend humanity. The losers will be kicked off the planet...forever!