Carly is a young teenager living in Seattle. When her friend Freddie accidentally leaks a video of her and her best friend Sam onto the Internet, they decide to create an online web show.

A ridiculous technicality costs Carly her straight A average. The next day as Sam is being punished, she manages to fix Carly's grades with the school computers(and for some reason, Freddie's), and makes her promise not to tell anybody. Because Sam's scheme involves Freddie, Carly decided to tell only him about it, and Carly can't decide whether the guilt over Sam's amateur hacking or Freddie's sophisticated effort to undo the fix will gnaw away at her conscience first.

Plans for the landmark 50th web cast of iCarly are at risk of being curtailed when Sam gets detention. Realizing she can't do the show without her co-host, Carly and Freddie try to get in trouble themselves, so they can do the live web cast from their school's detention room. However, deliberately trying to get detention proves to be far more difficult than Carly can imagine, and even harder for Freddie.

When Sam hears that Freddie is fed up with her "borrowing" money, and Carly convinces her his complaints are legitimate, Sam takes desperate measures to try to pay back everybody she owes, ranging from pleading for money on Carly's web-show to... of all things, getting a job! Meanwhile, Spencer volunteers to sell fudge-balls for a shy Sunshine Girl in order to impress her attractive single mother.

Sam and Freddie are forced to share a locker, while Carly seeks art lessons from Spencer.

Carly and martial-arts champ Shelby Marx (Zoey 101's and Spectacular!'s Victoria Justice) agree to have an exhibition fight for charity after Carly jokingly challenges her to a match. Unfortunately, Carly accidentally falls on Shelby's grandmother during a press conference. Thinking Shelby wants revenge, Carly backs out of the fight, only to be ridiculed as a coward. Carly visits Shelby and apologizes, and the fight is back on. However, Nevel Papperman alters a clip of the press conference to make it look like Carly intentionally tackled Shelby's grandma to dupe Shelby into fighting Carly. Shelby, furious, attacks Carly for real during the match, Carly then holds Shelby's leg for the rest of the "fight".

Principal Franklin is fired after appearing as a guest on iCarly and is replaced by Mr. Howard, the math teacher, and Miss Briggs, the English teacher as co-principals. Spencer hires a rodeo star to teach him how to ride a mechanical bull.

The cast introduces various bloopers and outtakes from the entire series.

When Brad and Freddie start hanging out, Sam wants to hang out with them too. After Freddie uses the app, it says that Sam is "in love." So Carly helps Freddie to hook Sam and Brad up. Meanwhile, Carly and Gibby do experiments on Spencer.

Sam and Gibby secretly operate a restaurant in the basement at school, while Spencer creates a security robot that goes haywire.