In this special April Fools episode, Carly and Spencer are being evicted, so the gang reminisces about their time in Bushwell Plaza. But their memories may not be quite how we remember them.
One Direction has accepted an invitation to perform on iCarly. Band member Harry becomes sick and Carly dotes over him. Realizing Harry is playing sick for the attention, they hatch a plan to get him back in the group by telling him Gibby has become their newest band member. Meanwhile, Spencer becomes a personal trainer and gives a bratty girl a makeover.
After their computer and TV have been stolen, Spencer starts developing a security robot. At first, he builds one that blinds intruders, but takes it apart after it blinds Carly. He then makes one that shoots corn at intruders, but it malfunctions and attacks Carly, Freddie and Spencer. They try to have it focus on Mrs. Benson and unplug it, but Spencer doesn't manage to pull the plug out of the outlet before the machine runs out of corn, so Mrs. Benson is heavily pelted with corn. Meanwhile, Sam and Gibby open a secret restaurant named Gibby's in the basement at school. Bully Billy Boots, who just got out of juvie, harasses and irritates Gibby. Sam tries to diffuse the situation by sending Gibby to go on a walk and trying to talk to Billy, but when Gibby returns later, Billy attacks him and Sam beats up Billy with a Butter sock. The next day, Billy tells Mr. Howard about the restaurant and hopes it gets shut down. Even though Principal Franklin, one of Gibby's customers himself, agrees that the restaurant violates school rules, he allows Sam and Gibby to keep running it in secret as soon as Mr. Howard is out of earshot.
Carly, Sam, and Freddie wonder why people can't celebrate Halloween more than once a year. They decide to celebrate it halfway through the year as well creating a new holiday termed "Halfoween" and have a party. Carly dresses up as a life-size serving of tuna sushi, Sam dresses up with a hat with "hand sanitizer" on it, and Freddie dresses up as Lewbert. Once Nevel finds out, he dresses as a purple robot and give the "iCarly's" candy, which changes their voice and freaks out many people. Because of this, they angrily split up to find out who the purple robot is. Freddie successfully finds Nevel in the iCarly studio. He calls Carly and informs her it was Nevel, but Nevel's friends E-von and Dimitri force Freddie into the robot costume. Nevel silences him and magnetically seals on the head so Freddie cannot take off the costume. Meanwhile, Sam and Carly get their real voices back, and Freddie probably does too. After Freddie is sent downstairs, he is caught by Gibby and Spencer. Still silenced Freddie is unable to tell his friends that it is him in the costume not Nevel. Subsequently he is suspended and lowered twenty times in Spencer's new game, Jerk Basket, everyone thinking that it is Nevel being punished. After Carly and Sam feel they have their revenge, they realize Nevel was right behind them, happily watching Freddie get jerked. Nevel unlocks Freddie's robot head and they find an angry Freddie. Spencer tries to apologize to him, giving him a free stuffed unicorn from the Jerk Basket, only for Freddie to throw it back at him. Nevel finally feels he has had his revenge for the"iCarlys" not rising his popularity. Carly pretends she feels sorry and lets Nevel stay at the party, but she makes Sam "dangle" him above Spencer's Jerk Basket. They finally let him fall, and he collapses in a huge pile of toys and such. All the partygoers clap and cheer as Nevel is then suspended once more, as he has finally learned his lesson and he will not try to get revenge.
When Freddie gets a new job at the Pear Store, Sam, who is employed with him, accidentally ruins it. Meanwhile, Spencer makes a fire for the 18th time and because of their tiredness, the fire department is done with the Shays and to apologize, Spencer brings a batch of brownies to the station. Unfortunately, the vengeful staff makes him volunteer at the fire station, which leads to another fire, this time at the station. Also, Carly meets a boy at the the Pear Store named Trey and becomes obsessed to get him to ask her out.
After Spencer's arch-nemesis Chuck pulls his latest prank on him and steals his clothes, Spencer finally gets rid of his nemesis by getting Chuck sent to military school. However, this causes Chuck's younger brother Chip to hate Spencer and terrorize him more than Chuck did. Meanwhile, Gibby buys a Galaxy Wars toy phaser and becomes depressed when Sam accidentally breaks it while beating up a bully. Freddie fixes it, but also modifies it into an actually working heat laserballoon. During an iCarly webcast, Chip antagonizes everyone with loud music, making it impossible for them to continue. Downstairs, they find Spencer, who has been tied up by Chip. Gibby sets his phaser on "Overload", causing it to overheat. Before it explodes, Spencer throws it down the hallway where Chip is preparing a tub of super glue for another prank. The exploding phaser blows up the tub, and Chip gets thrown back by the explosion and glued to the elevator's doors. When Spencer and the others go to check what happened and find him, Carly says that they can't leave Chip like this. Spencer agrees, then sprays cream on his butt before everyone leaves.
Jimmy Fallon invites the gang to New York after Carly dedicates a webshow to him parodying his famous skits. Gibby bought street pants and caused a few problems during the show. While the gang starts dancing, Gibby's street pants accidentally fall down and he isn't wearing underwear, causing the NCC to show up. People start to blame Jimmy for the incident by saying he deliberately wanted Gibby's pants to fall. Carly and her friends do an episode of iCarly saying it was their fault and not Jimmy's. The NCC forces them to pay 0,000 dollars or they will shut down iCarly, so Jimmy blogs asking America for their spare change to help the iCarly gang get the money.
Freddie and Gibby join a band. Carly bans T-bo from her apartment so he bans her from the Groovy Smoothie.
The gang tries to find Spencer friends his own age but Spencer finds them way too old! Gibby marries Baggles and starts working as a bathroom attendant.
Carly gets into trouble when she doesn't listen to Sam's cautionary advice about a pal who had just been released from a juvenile detention facility. Meanwhile, Spencer gets obsessed with a pair of night-vision goggles.
Sam learns that her mother, Pam is being held in a Las Vegas jail, so Carly and the gang embark on a road trip to Sin City, where they pawn some of their prized possessions for bail money at a shop run by the Pawn Star guys.
The gang tries to track down a thief when Sam's laptop is stolen; Spencer can only visit his favorite arcade if he is accompanied by a child.
Carly is sad when her father cannot escort her to a military dance; Sam and Spencer fix a motorcycle; Freddie gets a new phone.