Timmy is working on his homework. Cosmo askes him what he's doing, and he says he's doing his homework. Cosmo says, "but seriously, what are you doing?" Then, an unsuspecting van drives up to Timmy's house, and Mr. Crocker dressed like cake gets out. Timmy's Dad opens the door, and Mr. Crocker tells Timmy he's going to SUMMER SCHOOL... and there was supposed to be thunder and lightning, but Mr. Crocker blew his budget on the cake. Meanwhile, Sparky is making soup from Timmy's homework, and Timmy spazzes out.
Timmy then tries really hard to work on his homework, and eventually, he gets a 92. However, since Denzel was grading on the bell curve, Timmy got an F. This is because everyone else got a 93 and above. That's when Timmy comes home, and Wanda says she knows about his grades. Timmy wishes he could be the smartest person in the world. His head got really big, and he knew some terrible facts. He wishes to be changed back.
Timmy got a brand new idea. He wished everyone was DUMBER than him. That way, he can slack off on his homework, and since Crocker is grading on the bell curve, he would always get an A+. Somehow, his fairies end up with hot dogs, and are actually eating them. Poof says, "POOP POOP!" Everyone laughs, except Timmy. Dad comes to the door and can't open it because he thinks there is a force field around the house.
The next day, Mr. Crocker says there is a force field around the school, which is why he was late.. Timmy gets a 41 on his homework, and everyone else got a five or less. Crocker offers Timmy a hot dog, but the smoke from the Barbecue makes the Fire alarm go off, and the water system go go off, making Crocker think he made the ceiling cry.
Timmy brings home grades of 41, 15, and -4. The negative 4 was an A++++++++++, which means everyone else had the worst possible grades.
A meteor starts hurtling towards Earth. Everyone thinks it's a muffin. Crocker hopes it's bran. Timmy is the only one who knows it's a meteor, who sees it after mentioning that all he did to win the science fair is stick a lightbulb into a hot dog. Wanda believes the hot dog has an idea. Timmy has to figure out how to stop the meteor. He realizes if one hot dog powers a lightbulb, a thousand will power a rocket. Timmy's dad ironically wants to store a thousand hot dogs in his room. Timmy feeds his rocket the hot dogs, and the hot dog happens to be a vegetarian. The rocket blasts off and detours the "muffin". Everyone gets mad at Timmy, then wishes for Cosmo and Wanda to make everything normal again, but he has to tell Wanda to wave her wand when he says something.
Everyone is now smart, except Cosmo.