Earl gets so upset by inaccuracies in a game of ""dinosaurs"" Jeopardy that he decides to give the students a first-hand account of the early Mesozoic era by filling the halls with computer-generated velociraptors and T-Rexes! None of the kids know how to get rid of these massive monsters, except for Marcus, but he lacks the confidence to express his ideas. Only when he's urged to speak up does Marcus voice his plan to freeze the school and send the dinosaurs to the only local source of heat: Earl's boiler room! Marcus' plan saves the school and helps him build the confidence to express himself.

Inspired by a classic horror film, Mrs. Snodgrass builds an exact replica of an Egyptian tomb and brings it to class. Lydia mocks the movie, claiming that it is just a story, and that it has no basis in fact. Earl, a big fan of the film, becomes so enraged that he morphs the school into an Egyptian tomb. The gang has to find its way out of the maze of corridors to stop Earl and return the school back to normal. But when Lydia takes a scarab from the tomb of the Mummy, it sets in motion ""the curse of Pharaoh Phinster."" Marcus, also a big fan of the movie, knows what to expect at every turn because events occur exactly as in the movie. Lydia, however, doesn't believe anything that isn't documented in her reference book about Egypt. Each person has to listen to the others' views before they are sealed up in the tomb forever.

Ruby and Marcus get entangled in a sibling battle for personal space during a class on undersea life. When Ruby stops to giggle over a fish which looks just like Earl, Earl gets so mad that he floods the school with giant hungry fish! A lonely only child, Earl also abhors siblings who can't get along, and enjoys plunging them into ""an ocean of space""! Drawing on a home economics lesson about cooking, the kids plunge underwater in a pressure cooker to unclog the drain (and drain out the school). But Marcus and Ruby are so caught up in sibling strife that they threaten to upset the pot's delicate balance. Only when the two siblings agree to respect each other's space and work together can the kids successfully open the drain and flood Earl's boiler room!

Earl gets irate when Mrs. Snodgrass praises Billy and Marcus' model space shuttle as the most ambitious that she's ever seen. Earl hauls out his old model of the solar system and expands it to life size to remind her of his great work. But the planets are all out of order and turn the school into a massive galaxy that's going to hurtle the earth right into the sun! Billy tries to realign the solar system by knocking planets into their proper places with their space shuttle, but he takes short cuts which threaten to ruin the mission. Marcus reins in Billy's rushed effort and calmly figures out a way to divert the sun, sending it crashing into Earl's boiler room! Marcus saves the school, and Billy learns the value of careful preparation and planning.

Mrs. Snodgrass is introducing the great classic ""Frankenstein"" to the class just as Lydia arrives with a bulky new addition to her braces. Teased about her appearance, Lydia is made to feel like a monster by the other children. Earl, inspired by the genius of Baron von Frankenstein, decides to morph the school into a Bavarian village, complete with a deadly and ferocious monster. Raticus is sent out to retrieve body parts for Earl's creation, but he substitutes a big wad of bubble gum for the creature's brain. The monster turns out to be sweet, bumbling and misunderstood instead of fearsome and dangerous. Lydia and the monster, both feeling outcast because of their looks, have to prove to the others that you shouldn't judge a person based on their appearance.

Earl is furious when Mrs. Snodgrass's class doesn't recognize him as one of history's greatest villains. To show everyone who the world's greatest fiend really is, he launches a full scale, tactical war, and he sends a troop of treacherous, life-sized comic book villains in to conquer the school. Although the boys think that they are the only ones with enough comic book knowledge to thwart the evil villains, they soon realize that they know nothing about these characters! Fortunately, Lydia's knowledge of comic book trivia is tremendous, and she's the only one who can identify each villain's weakness. Lydia and the gang defuse Earl's latest attack, once again saving Flying Rhino Junior High from impending doom. Impressed by Lydia's trove of comic book knowledge, the all-male comic book club realizes that boys and girls can not be stereotyped, and it invites the girls to join.

Despite her wretched singing voice, Ruby is awarded the lead role in the school musical. When her fame goes straight to her head and her monstrous ego begins to irritate everyone, Earl recognizes a perfect opportunity to agitate the gang even more! Matching Ruby's DNA, he repeatedly clones her and her mammoth ego until the school is running rampant with Ruby's -- each one fighting for the center of attention. Billy and the gang fight hard to remain sane and, with a little help from Marcus, they discover a way to destroy every Ruby. Marcus cranks up the radio frequency on his Mega-mind, causing all of the Rubys -- and Earl's computer -- to short-circuit! Sanity is restored to Flying Rhino Junior High, and the real Ruby realizes that she doesn't have to be the center of attention -- at least not all of the time.

Marcus' stamp collection is of no interest at all to his friends. However, one of the stamps catches their eye. Marcus' 1918 ""Curtiss Jenny Inverted"" stamp, one of the rarest in the world, is worth over a million dollars! The gang smothers Marcus with attention, but it's clear that they're only interested in his stamp for the money. Earl, meanwhile, wants Marcus' stamp for his own stamp collection! Morphing the school into a stamp factory circa 1918, Earl tries to steal the precious postage right after it's made! The kids prevent Earl from stealing the stamp and changing history, but not before learning that greed should never be a motivation for appreciating something.

Billy is busy boasting about how well he plays Marcus's new medieval castle video game. He is so keen to prove his ability that he plays during class, but he gets caught by Mrs. Snodgrass, who confiscates Marcus' game forever. Earl fondly remembers the world's first video game, which he invented. He, too, had been caught playing in class and had his computer game confiscated, robbing Earl of all his video game fame and glory. Earl becomes increasingly angry over his lost opportunity, and he turns the school into the game ""Wolf Castle 3D."" The gang counts on Billy to see them through, since he knows the game so well. Facing villain after villain, Billy is finally forced to confess that he never played the game at all, and that he doesn't know a thing about it. Luckily, Marcus does know the game -- very well, since he created it. Billy, Lydia, Marcus and Ruby work together to hack into Earl's computer and turn the school back to normal.

Earl rejects Raticus' wish that they celebrate the Christmas holidays together. Unfortunately for Earl, his own wish of having no Christmas is granted when he's paid a visit by the Phantom Raticus! Using Earl's computer against him, Raticus subjects Earl to a world where holidays don't exist -- because the school day never ends! Earl wakes up to discover that it was only a bad dream, but not before realizing how important it is to be with friends and family during the holidays. Morphing the school into a winter wonderland, Earl and Raticus enjoy Christmas festivities together.

Billy is the only student who didn't make his own Earth Science project to be judged in class. He put off building the ""weather nullifier"" that he designed, using the time to play baseball and watch TV instead. With no time left to make the project, Billy ends up having to buy one. Before the judging takes place, Earl submits his own project, a ""preter atmospheric generator"" that he believes will win. When it doesn't, Earl angrily turns it on, unleashing a tornado, a mudslide and a thunderstorm on the school! When Billy's nullifier fails to work, he finally builds the one that he was supposed to for class. Only then is Earl's weather attack stopped, and a lesson in the perils of procrastination learned.

Marcus spends so much time with his latest creation, the ""Pal 9000"" minicomputer, that Billy feels left out. But Billy's not the only one irked by Pal, for Earl sees Pal's prowess as a challenge to his own supercomputer! Earl shows off his techno-might by turning the school into the edu-station of the 23rd century: a facility run by a computer gone berserk! Marcus uses Pal to take over the building's errant computer, but Earl strikes back by infecting Pal with a virus, causing him to attack students with the building's desks, chairs and doors! Billy tries to warn Marcus that Pal is infected, but Marcus, thinking that Billy is just jealous, refuses to listen. Only when Marcus sees his friends under attack does he finally take action, cleansing Pal with an anti-virus program. With the help of Billy and Marcus, Pal travels through cyberspace into Earl's computer and completely destroys it, saving the school!