Penn returns to the world of superheroes, only to discover the heroes have been turned evil by Captain Super Captain's evil twin brother, Professor Evil Professor.
This is the first episode for a dimension to be seen a second time, in this case the Superhero World from "I'm Super!".
However, as revealed by events shown in the flashback from "Zap One", this episode isn't the first time the characters have revisited a dimension.
In this episode, some of the names of inhabitants of Superhero World are revealed; Giant Old Lady's name is Suzanne and Professor Evil Professor's name is Clarence.
Penn Zero: Part-Time Hero (Opening Theme) • We're Breaking Out of Here for Christmas • Time to Kill • We Can Catch the Milkman • What is a Princess? • Pigoilet • Victory is Mine at Last • The Truth of It Is • Moonlight Bright • This is a Real Song • Boone Reads On • Race to the Top • Race to the Top (reprise) • You're a Karaoke King • High in the Sky • Breath In, Breath Out • Bad Weed • Today's The Day • My Name is Penn Zero • Save the Worlds • In the Splishy Splashy Sea • Come Aboard with Me • Training to Win • Wings of Destiny Song • Sometimes We Need a Friend • Build and Backup Now • The Time Table • Everybody Chillax • Why Won't You Turn Green • It's the Best Friend Song • It's the Best Friend Make Up Song • Grinkon's Song • Its Not Just Today
Middleburg • Middleburg Central High • The Odyssey • Fish Stick on a Stick • North Pole • Knight World • Superhero World • Arabian World • Plush Toy World • Clown World • Dinosaur Cowboy World • Cereal World • Old English World • Giant Monster World • Zombie World • Space World • Ocean World • Color World • Musical Fairy Tale World • Caveman Spy World • Future Barbarian World • Ultrahyperball World • Demon World • Alien World • Galaxy World • Temple World • Dragon World • Gothic Mystery World • Plant World • Animal Barbarian World • Toy World • Outer Space Court World • Robot World • Pirate World • Fairymania World • Steampunk World • Ball World • Ghost World • Rock, Paper, Scissor World • Beast World • Anime World • Sitcom World • Nothingness • Most Dangerous World Imaginable • Least Dangerous World Imaginable
Objects
Multi-Universe Hologram Uplink • Multi-Universe Transprojector • Pigoilet • The QPC Unit • Vortex Tops • Specs