Lewbert, Carly's doorman, is injured during an exploding muffin basket prank. Spencer suggests that Carly, Sam, and Freddie help him until he's back on his feet, but it is more easily said than done. When Freddie's mother takes over, she makes it look easy, but leaves the group extremely concerned. Freddie's mother and Lewbert fall in love. Meanwhile, while using a CB radio, Spencer upsets two truckers nicknamed Porkchop and Sledgehammer.

Carly's old friend Missy Robinson returns to Seattle and tries to become Carly's only best friend and replace Sam because she was Carly's best friend first. Sam was given expired chocolate by Missy, and she destroyed Sam's cell phone, and in addition, Missy texted Sam the wrong address to a helicopter base, that she intended to go on with Missy, and Carly. Missy's actions are claimed "accidental", however Sam realizes what Missy is trying to do, but no one believes her as they think Sam is being "her usual paranoid self", because she was being paranoid when she thought Lewbert was an undercover cop, because she thought his giant wart was a spy cam and thought Gibby was a mermaid because he doesn't like wearing shirts. Missy confesses to Sam, but since no one will believe her, she is forced to ask Freddie for help, so when Freddie wins a six month cruise, he gives it to Missy so she will go away. Shortly after Missy is awarded with the cruise, Carly discovers Missy's plans to destroy her and Sam's friendship. Meanwhile, while packing for a camping trip, Spencer is locked in the basement by a psychotic boy, Chuck, seeking revenge from Spencer for telling on him and getting him grounded in the episode "iHurt Lewbert". Chuck is eventually caught at the end of the episode and is grounded by his father.

Sam has a twin sister named Melanie (Portrayed by Jennette McCurdy). Freddie is not convinced, and to try to prove it, he sees Melanie in person and invites her to a dance with him as his date. The plan to try to prove that Melanie is really Sam takes an unexpected turn when Melanie kisses Freddie, who then becomes extremely paranoid. Meanwhile, In the end, since Freddie refuses to believe it, Sam admits to Freddie that there is no Melanie. Satisfied, Freddie departs right before Melanie (who reveals that she still has romantic feelings for him) arrives to go to the mall with Sam and Carly. Meanwhile, Carly tries to tutor Chuck in math, and Spencer shows Carly how evil Chuck really is (with the help of a hidden video camera that Socko set up). Carly gets revenge on Chuck by telling him there's a new number called "dirf" between 5 and 6, and because of this, Chuck fails his math test and Spencer gives his dad a brochure about a summer math camp called Camp Add-m-Up, sending Chuck to math camp for the whole summer.

After a prank on Lewbert Sam loses her phone in his office, when her and Freddie get it back Sam steals a personal box from Lewbert’s office. Sam, Freddie and Carly look through it, only to find some interesting stuff about Lewbert, biggest him having had a girlfriend. Getting an Idea they set out to reunite him with her so he can be happy and leave them alone, only to find out Lewbert doesn’t exactly “like” her. Meanwhile after a rash of robberies Ms. Benson signs Spencer up to a watch group with a little pest from his past.

Spencer comes to the rescue when a heat wave hits Seattle and the power goes out.