Marty and Underworld Marty swap places on Halloween, Underworld Marty goes trick-or-treating with Burnie and Holly, while real Marty is trapped below, where the underworldly inhabitants want to make a meal of him.
When Super Simon has to go and do his scout badges, Marty is thrilled to help him. But Super Simon takes all the credit and Marty gets jealous and sabotages his hero - forgetting the true meaning of Toon Scouts.
Jack quits the Toonmart and gives it to Burnatron so he can fulfill his bucket list - and discovers that he's a natural daredevil. But Marty vows to himself to get Jack back where he belongs: The Toonmart.
When Marty gets a gold-grill after losing his teeth, he becomes super cool and hangs out with Super Simon and his cool guy posse. But he gets bored of them and tries everything to hang with Burnie and Holly again.
Marty beats the toughest monster in Toonville and is declared a hero. But he grows tired of his hero status and he vows to reset everything. The problem is Toughy turns out to be a pacifist. Cue the staged fight.
Holly's logic board jammed and she vows to destroy all toons because they're illogical. She turns Toonville into real things, until Marty puts on a toon display of unmatched proportions. A display so toony it saves Toonville.
When Chef tires of chasing Chicken he finds an even better prey: Marty. Or so he thinks. Chicken helps Marty escape Chef's cleaver, and Marty gives Chicken some etiquette training to get her old job back.
Marty gets so smart that his head expands. Dr. Smartypants tells Holly and Burnie that if he learns one more thing his head will explode. While keeping all new information from him, they try to bring him back to normal.
Marty is super excited about his birthday, but when he finds out it's also Carly's birthday, and that he has to work her preschool party at the Toonmart, Marty stops at nothing to reclaim his special day.
When Marty takes over the doctor's annual job of recalibrating the toons, he and Suki make a mess of things. Marty races against the clock to get their calibrations to stop Toonville from exploding into the toon-abyss.
When Marty and Burnie take over Holly's webseries, they steal her spotlight and her robo-super-fans. But the robots hijack Marty and Burnie's lives and it's up to Holly to help them lose their super-scary super-fans.
When Burnie loses the use of all his senses, Marty volunteers to be his surrogate sensor via the use of painful sense-leeches. But when Burnie abuses Marty's good graces he puts them both in head-exploding danger.
When Marty's hat is stolen by Hobo Jeb, everyone thinks Hobo Jeb is Marty! Holly and Marty have to get the toons to look past the superficial. And when that doesn't work, well, he has to steal his hat and identity back.
Marty finds himself in the second part of a "To Be Continued" episode, with no recollection of what happened in the first part and everyone is depending on him to save Toonville! To be continued...