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.

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.

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.

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.

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.

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.

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.

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.

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.

Jessie is worried about failing the eye-test, but his attempts to cheat end up with him having to wear glasses, making it hard for him to see anything. Meanwhile, Nancy and Charlie are competing to be voted best athlete in the class and Nancy thinks she has worked it so that they will tie, but when Jessie is unable to see the ballot paper he accidentally votes for Charlie, winning him the vote.

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.

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.

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.

All of the girls get excited when they see the new Cleopatra hair-style by Simon of London and in an attempt to become more popular, Nancy tells the others that she is going to get her hair cut by Simon. After begging her mom and promising that she won't ask for anything ever again, Nancy finally manages to get to the hair salon, but the resulting style from Nigel the cleaner makes her look more like a poodle. Meanwhile Polly can't stand it when Freddie gets a better grade than her on a paper on butterflies and insists that Miss Graves remarks them, sparking a debate that eventually leads them to Mr Besser's office.

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.

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.

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.

As election fever hits the school, everybody seems to be running for class president except for Polly who is off ill. When Nancy is made to go round and see how Polly is, she lets slip about the elections and Polly forces herself well again in order to stand for president, forcing the rest of the competition out of the race and winning by default. However when the kids grow tired of Polly's forceful ways, they lead a revolt to force her out of power.