Jesse gets the math book with the answers to the tests by mistake and it helps him become "smart". Because of this, he wins a prize at the math competition, but finds out that he has to answer the math questions in front of the whole school. Meanwhile, Nancy pretends that she has difficulty listening so she can sit up front with Penny, but instead she is sent to see the school nurse.

Nancy returns from her trip to Mexico ready to show off her tan and her new charm bracelet, but when class starts the kids are more interested in the choosing of the new crossing guards. When Miss Graves selects Polly and Arthur as the new guards, the kids soon discover that both her choices are a nightmare to have helping you cross the road. While Polly insists that every student learns the seven safety tips, Arthur begins charging people to cross at his corner. When Polly is almost hit by an ice-cream truck, Miss Graves learns that Arthur has been charging and forces him to use the money to buy Polly a get well present and when Arthur gets to the crossing the next day, he learns that crossing lights have been installed. Meanwhile Nancy's good luck bracelet goes missing and she tries to find out who has stolen it, only to discover that it was never stolen in the first place, it just got misplaced in her coat.

Jesse becomes an outcast after Freddie tells everyone that Jesse ate a piece of chewed gum that he found under his desk. Meanwhile, the kids try to watch a part of a documentary named "Chinook from the North."

Jesse is thrilled when he is teamed up with Freddie and Polly (the smartest students of the class) to present a committee report, because he figures they'll do all of the work and he'll get the credit. Meanwhile, in order to match with her friends' fashion, Nancy buys a fur hat, but it's too big and everyone laughs at her.

Arthur loses his ring, but when he goes to the lost and found office to try and find it he finds himself up against Polly who insists on him filling out sheet after sheet of paperwork and decides that it isn't worth the effort. However when Mr Besser comes back on duty, Arthur takes the opportunity to look for his ring, but rather than taking his own ring he takes somebody else's. Signing up to work in the lost and found office, Arthur volunteer Polly for a role as trash monitor and is soon taking whatever he likes from the collection. However when Miss Graves finds Arthur's ring, he demands it back and realises that what he has been doing is wrong, returning all the lost items to their rightful owners. Meanwhile Jessie becomes funny when he buys a book of 101 insults, but on the eve of Mary-Ellen's party he uses up all of the insults and is instantly booed off stage when his improvisation proves to be the unfunniest thing ever.

Nancy is excited when she is partnered with a new boy on a trip to a museum, only to learn that he doesn't speak any English. Arthur and Freddie try to find the vacancy toilet around the museum. Jesse tries to run away from his mother who joined the trip as a chaperone.

Vinnie and Jessie find a list of teachers' phone numbers and decide to prank their teachers, however after Jessie calls Miss Graves, Vinnie is caught pranking Mr Besser and is forced to be his helper for a week. The next day, Miss Graves asks Jessie what his phone number is and he begins to worry that she is going to phone his mom about the phone pranks. In an attempt to intercept the call, Jessie fakes illness in order to stay home and guard the phone, but when he returns to school the next day he learns that Miss Graves only wanted to call his mom to tell her that he had won the perfect attendance award, but seeing as how he missed school she didn't need to call her. Meanwhile Nancy becomes friends with Polly in order to join Penny on a trip to the International Lithuanian Dance Festival, but when Penny has to stay home sick she refuses to come, not wanting to get in the way of the close friendship that Polly thinks has grown between the two girls.

Polly becomes a junior librarian and is determined to reclaim all of the library's overdue books, driving everyone crazy in the process. Arthur collects the books from his friends and opens his own library.

Arthur pretends to leave his lunch at home when he learns that the cafeteria workers give great free meals to kids who forget their lunches. Meanwhile, in order to get revenge on Zack after he bullied her, Nancy tries to learn karate.

Nancy arrives at school and immediately begins bragging about her new boyfriend Jeremy, and while the other girls are impressed to begin with, they quickly become bored of Nancy's stories and Tilly begins to doubt that Nancy even has a boyfriend. When Nancy and Jeremy meet up after school she tries to make him change his image and the next day he fails to turn up for their date. When the girls ask to meet Jeremy, Nancy tries to put them off meeting him, worried that he won't turn up, and they become even more certain that Nancy is making the whole thing up. However when the girls eventually do get invited to meet Jeremy, he turns up just as they are leaving, much to the shock of all of them. Meanwhile Jessie starts borrowing Freddie's homework to copy it but is caught out when Miss Graves sets Freddie a special assignment instead of the regular homework.

As Sports Day approaches, Nancy is sure that she will win all the events she enters, but as the flu season hits she becomes increasingly concerned about falling ill and missing the even. However as she tries to protect herself from the germs she ends up losing every event that she had entered and eventually gives up her principles to take part in the potato sack race with Penny who is ill. Meanwhile Jessie injures his nose while rollerblading and uses the injury to get out of doing schoolwork, however when he makes a miraculous recovery to paticipate in Sports Day, Miss Graves makes him water boy as punishment.

During practice for the Chorus recital, the music teacher starts to give birth and practice ends before Arthur can rehearse his solo, and when Mr Besser becomes the new music teacher, things go from bad to worse. However Arthur calls in a few favours and Mr Besser is replaced by the hopeless Mr Jackson who is keen to work on Arthur's solo, until Polly suggests that she and Arthur perform it as a duet. As Arthur grows more and more annoyed with Polly's interfering he decides to change the words, upstaging Polly when the two perform the piece. Meanwhile Jessie cuts the pictures out of the encyclopaedia to get a good grade on his Mammals report, but when his plan to put the pictures back goes wrong, Miss Graves finds out and forces him to clean every book in the library.

Picture Day arrives and Freddie is really proud of his cowboy shirt until he finds out that Polly is wearing one just like it, but his attempts to hide the fact quickly fail and the class makes fun of him all day. However when it finally comes to taking the picture, Miss Graves positions Freddie behind the board giving the name of the class to avoid him being embarrased by the photo. Meanwhile Jessie fakes an allergic reaction to get out of doing the Science test but is forced to do it anyway and fails miserably.

In order to eat the same foods as Penny, Nancy goes to the health store and ends up being scared into trying a totally healthy diet, and soon all of the girls are eating only healthy foods, resisting temptation to eat their favourite foods. Meanwhile Freddie's birthday approaches and in order to get more tickets during the trip to Monster Land, Vinnie and Jessie persuade all of the other kids not to go, however on their first ride on the Bllod Drainer the ride breaks and they are stuck hanging upside down for three hours. When Freddie comes to school the next day, he brings his cake with him to share with the class and while Vinnie and Jessie are too ill to eat any, Nancy gives up her diet to have a piece.

Polly takes over reading the announcements over the school's public address system and soon starts to broadcast everyone's misdeeds. Meanwhile, Jesse stays at home for few weeks due to his ankle injury. At first, he wants to have fun, but Miss Graves decides to make him participate in the class with the help of the camera.

Jesse and Vinnie enter a science fair when they learn that the winners get to go to Space Camp, but they are caught cheating. Nancy and Penny do a project about bugs for the science fair. Polly chooses Freddie and they make a project about spoons, which Freddie sabotages.

Nancy has a lot of bad luck and learns that Mercury is in Retrograde. This means she might miss a baseball game, but at 2.15 PM everything will be the same again. And poor Freddie had to go to the toilet, but spoils a bit water on his pants, but the kids believe he was peeing in his pants.

The kids are very thrilled to see a new car during their baseball game, until they realize the new car is Mr. Besser's car. He doesn't want the kids to mess with his car. But when Jessie boasts he did it, he is sent to Mr. Karl's class. At first, he thinks it's a nightmare, but because the kids in Mr. Karl's class are dumb, Jessie takes advantage of this punishments and never wants to leave the class. While Jessie is having fun in Mr. Karl's class, the rest of the class is overkilled with fire tests. Arthur knows this and invites kids during the fire tests.

Polly becomes popular when she gets a pony, but as the kids all take turns to meet Snowball they find out that it's not as great as they thought as Polly forces them to answer questions on ponies before she will let them near it. Meanwhile Jessie pretends to have sent his book report to his Nanna and Pop-Pop's by mistake to stop Miss Graves from grading it.

Jessie's mom finds out that the other boys are bullying him and tries to help him out, but only ends up embarrasing him further. Meanwhile Nancy finds out that Jordan is really rich, but the other girls soon get tired of her bragging.

The girls get excited when a new ping-pong table is introduced to the playground, but deciding who gets to play first causes problems as each method of choosing meets with conflict from everyone else. Meanwhile Vinny and Jessie pick up some swear words at the arcade and start using them around school

The Squirrel Girls hold their annual cookie-selling contest for two girls to win places at Squirrel Camp, but Nancy's ruthless tactics to go on camp with Penny end up forcing Penny out of the contest, meaning that Polly wins the other place. Meanwhile Jessie is forced to have all of his shots when Polly decides to check out everyone's medical cards.