Lex releases all the prisoners and takes down the league of freedom. So it's up to titanium Rex to save his teammates.
Lex betrays the League where she devolves Cooch, depowers Brad, and traps American Ranger in a time tunnel. She teams up with Dr. Devizo where she releases him and the villains Blue Menace, Groaner, Buster Nut, Chet, Blazar, Bugula, Robo-Dino, Johnny Rabdo, Rat-A-Pult, and Quiplash from SuperMansion's prison. Lex reveals that her mother is Frau Mantis and wants revenge on Rex for letting her mother die in the fall.
Much to the shock of Rex and Saturn, Lex has the ability to change gender thanks to inheriting her mother's mantis DNA; Saturn faints in response. Dr. Devizo plans to launch nuclear missiles with the codes that Lex stole from Ivan Whiff and puts the League in their own prison. They escape and fight the villains where Groaner released Black Saturn since it would be difficult for him to find another worthy superhero for him to fight as Chet is accidentally evolved. Titanium Rex blinds Lex, Black Saturn devolves Blazar to a monkey, American Ranger rescue Gloria from Blue Menace, and the League of Freedom stops Dr. Devizo. Brad sacrifices himself to destroy the mainframe by burrowing into the underground lava to save the world, but the mansion is destroyed in the process and the League mourn for him while the villains get away. Even Sgt. Agony mourns him as he admits Brad was the only League of Freedom member he liked.
Three months later, the mansion is getting rebuilt and a statue of Brad is dedicated to him.
