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.

Nancy is embarrassed to learn that she has asthma and tries to hide it from her classmates, but soon finds that she is worried about every little thing that could cause her problems. She goes to see an alternative doctor, Dr Dedorio, who gives her a supposed miracle cure and Nancy begins to believe that she is getting better until she has an asthma attack during a game of soccer. Deciding to start taking her medication again, Nancy quickly recovers and learns that she isn't the only kid in Room 402 with medical problems.

As the class prepares to go on a school trip to the museum, Arthur has trouble going to the bathroom while other people are in there. Just before the class boards the bus, Mr Besser introduces Johan, an exchange student who will be going on the trip with Miss Graves' class and Nancy is picked to be his chaperone. The kids prepare to board the bus just as the class chaperone, Jessie's mother, arrives and immediately begins humiliating Jessie with various stories and photographs of him. When the group arrives at the museum, Jessie and Vinnie find themselves trying to escape Mrs McCoy who is desperate to pair up with them and Arthur, still in need of a bathroom, ends up partnered with Freddie. As Arthur searches for an empty bathroom, Freddie finds that he has also become kidney shy and the two desperately seek an empty rest room without success until Miss Graves recommends they visit the fourth floor exhibit on ancient napkins, the only place in the museum with an empty bathroom. Meanwhi

Nancy and Vinny start going out after they find they like each other while cleaning the classroom, but as Nancy thinks everything is going perfectly she discovers that Vinny is cheating on her with another girl. Meanwhile Arthur learns that his aunt is throwing him a surprise pool party but he doesn't know how to swim and signs up for lessons, only to find out that Polly is the teacher.

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.

The kids all get excited about the chance to see the ""Your Body is Changing"" film, until they learn that they have to go with a parent. Jessie thinks he's got away going without a parent until his mom turns up and manages to totally embarrass him, making him miss most of the movie and not finding out where babies come from. Meanwhile Polly opens up her Spoon Hospital for another year, but tragedy strikes when she accidentally breaks lunchlady Martha's serving spoon.

Shocked by Jessie's consistently poor maths scores, Miss Graves recommends him for the remedial program, but rather than attending the lessons Jessie spends the time bowling and going to the cinema. However when he finds out that his improvement is going to be tested, he bribes Sanjay to take the test for him, but the miraculous increase in his scores ends up with Jessie being moved from remedial maths to advanced maths. Meanwhile Polly sets up a stall selling spoons in school but finds that interest amoungst the other kids is low.

Miss Graves is called to the doctors when it is believed that she has medical problems until it is revealed that it was just a mix-up, however rather than returning to school she decides to take the rest of the day off. Back at school, Mr Besser is forced to take over as the substitute teacher for the class and soon appoints Polly to take over his duties in order to get rid of her infuriating ways. When Vinnie writes an essay in which he calls Mr Besser a cold hearted liver butcher, he thinks that he is going to end up in permanent detention until he realises that he has misspelt Besser, saving himself from 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.

All the kids are excited as the school fair approaches and every one of them is determined to get their hands on the two bikes up for grabs. As the stalls get under way, it seems that every kid has their own way to try and mnake the most money, however while the others are concerned with running stalls, Arthur is offering to promote each stall if the other kids pay him and then takes all the custom by offering kids the chance to win a stereo if they can knock down the cans at his stall. As havoc prevails at each stall, the kids are all eager to learn who has won the bikes when they find that the hopeless Mr Jackson has collected up all of the money without counting it first.

Jesse is tired of failing math. When it is time for the class to get new math books, instead of getting a student's text, he gets a teacher's edition with all the answers! Instead of reporting this, he uses this, only bringing his D minus average to an A average. When Jesse competes with Penny in math for an award at school for Monster Land tickets, he, of course, beats her by one point. When he finds out Penny's sick aunt died without Penny getting to say goodbye, he starts to feel guilty.......NOT FOR LONG! He says, ""I'm goin' to Monster Land!"" Just as Jesse is about to receive his award, Mister Besser decides to give him a tough math question to show everyone his ""genius,"" which Jesse couldn't figure out, he crashed and burned, forced to give the award to Penny.

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 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.

As Haloween approaches, all the kids are excited about what costumes they are going to be wearing. Vinny and Jessie both agree not to go as Space Beasts, but both then break their promise, however while Vinny comes in a proper Space Beast costume, Jessie's home-made version makes him look more like a mermaid. Mr Besser is determined to go as a pirate, but when Vinny and Jessie teach his parrot bad words they both get found out at the party. Meanwhile Nancy finds out that Penny is going as Little Bo Peep and decides to buy the same costume, but when she arrives at the party she can't find Penny, only a person dressed up as a sheep. Assuming that it must be Penny, the two enter the costume contest together, only to find out too late that it is actually Polly inside the costume.

After tricking Mr Besser with a dollar tied to a piece of string, Vinnie and Jessie are both sentenced to be his helpers. As well as the horror of doing the principal's duty, Jessie also has a spelling test to look forward to until his mom tells him that he is going to have to stay at his Nana and Pop Pop's because she and his father are going away for a few days. Excited at the prospect of missing the test, things aren't as great as they seem when the house is snowed in and the power blacks out. Jessie tries to make the most of it, but as things start to get better his mom arrives to collect him, bringing with him the spelling test so that he can do it on the way home.

Miss graves starts driving Nurse Pitts to school, but soon fnds sitting in a car with the nurse is no better than working with her. As the strain of the journies begins to show, Jessie and Vinnie take advantage by trying to convince her that she is becoming forgetful by hiding tests and asking for grades for papers that they haven't written. In an attempt to relax, Miss Graves visits a psychiatrist and, realising that the two boys have been stringing her along , decides to get her own back. She also confronts Nurse Pitts about the nightmare car rides and the nurse decides to catch lifts with Miss Belanchof instead. Meanwhile, Nancy is frightened by tales of Billy Woofchuck, a boy who was supposedly killed answering a telephone in a storm, and soon become too scared to even touch a phone while it is raining.

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.

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.

Nancy is thrilled to be going to her grandparent's in Miami for summer vacation, but when she arrives she soon finds that things aren't as great as they seem. The other guests are boring, the restauraunt is horrible and no matter what Nancy tries she seems destined to be banned from using the pool. However when Polly arrives at the site she and Nancy manage to work together and have a great time, but as the two arrive back at school Nancy is still determined to stay away from Polly as much as possible.

In order to not have to perform Mr Flop-Flop the Christmas Bunny at the school play, the kids band together to force Mr Besser to hand over control to them, however the ensuing arguing ends up with Nancy taking control of the play, much to the annoyance of the others. When the day of the performance arrives, Nancy and the others all end up stealing each others lines and although the play is a hit with the parents it turns out to be rather unconventional.

Fed up with her daughter's lack of respect, Miss Belanchof grounds Melanie and stops her from going out after school. In an attempt to get out of being grounded, Melanie starts sending herself fake party invitations, but when her mom catches on she is forced to sign up for cheerleading practices.

Nancy finds Mrs. Graves grade book in her backpack and she is determined to find some way of sneaking it back. All Nancy can think about is finding the grade book and about going to the principal's office, but Mrs. Graves finds it and Nancy had her chart book.

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.