"Super Zero" Billy wants to be a superhero like the ones on television and asks Grim to turn him into one. With Billy gone into space to stop an evil empire, Grim has to help Billy's father to build a shed. "Sickly Sweet" Grim and Billy give Mandy a mask that will turn her into a monster if she is mean at any time. Very quickly she turns into a hideous beast, much to the delight of Grim and Billy.
"Bearded Billy" Billy tries to take an example from his father, who hates to shave, but does it because his mother likes it. So he gets some hair tonic. But unfortunately it makes him grow into a hairy sasquatch. "The Nerve" Billy wants to steal Mandy's nerve so that he can stand up to Sperg. So Grim shrinks Billy and puts her inside of Mandy's ear where he steals Mandy's tough nerve.
"Attack of the Clowns" Billy has recurring nightmares about clowns, so Mandy devises a plan to rid him of the dreams. The plan backfires when the clown Grim animated starts to terrorize Billy. "Complete and Udder Chaos!" When Eris returns home from her job, she finds out that Grim allowed Billy and Mandy to use the apple of discord for their own fun and in the process created a huge amount of mischief.
"Test Of Time" Billy is given a history assignment based on Steven Hawkwing's "A Not So Brief History of Time!" Using Grim's Universal Remote Control, Billy finds that he can control time and hopes to use it to study longer.
"Five-O-Clock Shadows" Billy is afraid of his shadow, so he asks Grim about them. Grim tells him about the Shadow World and soon Grim, Billy, and Mandy are in the Shadow World.
"Whatever Happened To Billy Whatshisname?" Billy gets fed up with Mandy always bossing him around, so she replaces him with someone else. But then Billy gets jealous."Just The Two Of Pus" Grim agrees to clear up Sperg's skin if the bully can be nice to Billy for a change.
"That's My Mummy" While over at Irwin's house, Billy becomes convinced that Irwin's mother is a mummy. The curse continues to hurt Billy to the point that Grim and Mandy feel that they have to get involved. "Toys Will Be Toys" Mandy convinces Billy that everyone is laughing at him because he still plays with dolls. But instead of helping Billy kill the dolls, he shrinks Billy and brings to life the dolls for one last adventure.
"The Secret Snake Club" Mandy joins the nerds of the Secret Snake Club and is bored silly, while Billy joins the Junior CIA, which tries to transform him into a professional spy.
"He's Not Dead, He's My Mascot" Billy is asked by Mindy to make sure the school mascot, Fluffy Cat, is not kidnapped by the opposing team. But Fluffy Cat is a monster."Hog Wild" Billy accidentally ruins his father's new motorcycle, so he asks Grim to help rebuild it.
"The Bad News Ghouls" Mandy vows to destroy Billy's baseball team when he excludes her from the game because she is a girl."The House of No Tomorrow" Bored while at an amusement park, Grim, Billy, and Mandy enter the "House of Tomorrow," which is filled with neglected robots.
"Happy Huggy Stuggy Bears" Mandy gets offered a job as the spokeswoman for Happy Huggy Stuffy Bears, unaware that her new employer is Eris in disguise."Secret Decoder Ring" Billy wants to use the decoder ring he found in a cereal box to learn the secret of the universe, but soon he finds out that everyone else in town has the same plan.
"Wild Parts" While sleeping, Billy's nose is stolen by a noseless monster."The Problem with Billy" Billy's father tries to explain to Mandy and Grim that Billy was a child protege.
"Chocolate Sailor" Billy wants to make money by selling Chocolate Sailor chocolates, but ends up eating all of the profits. The more he eats, the more he starts to turn into a chocolate eating monster. "The Good, The Bad And The Toothless" Sperg knocks out Billy, while knocking out Billy's lose tooth. While unconscious, Billy imagines he is in the Old West trying to recover his tooth from the Tooth Fairy.