At the Chum Bucket, Karen dumps a bag of chum onto a tray and zaps it into a three course meal, the entree being chum pot pie. She goes to Plankton, who works on a project. Annoyed, he tells her the pot pie chum was supposed to be a stir fry chum, and she responds that her memory is full. Plankton says such problems will be solved by newest creation, which he reveals to be Karen 2. Karen is distraught that Plankton is replacing her, and his words anger Karen to the point where she tries to zap him. He flees from her blasts, but Karen 2 shuts her off via the Chum Bucket's power source. At the Krusty Krab, it's closing time, which makes SpongeBob sad. Mr. Krabs walks home as SpongeBob follows him and says good bye until he trips over a box filled with Karen's components. Mr. Krabs is about to get away until SpongeBob points out the "free" computer. Mr. Krabs rushes back, feeling anything free should be taken.
They go back to the Krusty Krab, where they activate the computer, who turns out to be Karen. SpongeBob is wary that it may be one of Plankton's schemes, but Mr. Krabs is convinced that anything free is automatically good. When Karen's startup is completed, the screen turns to a face, crying. SpongeBob tries to comfort her, but he unintentionally makes her even more depressed. Karen looks out the window of the Krusty Krab, where she sees Plankton and Karen 2 having a romantic dinner at the Chum Bucket. She angrily says she never wants to see Plankton again, and Mr. Krabs welcomes her to the Krusty Krab crew.
The next day, Squidward walks in to see Karen is at his post. He is baffled until Mr. Krabs explains that she will be doing his cashier duties for free. Squidward jumps for joy at the thought of no longer working at the Krusty Krab and dealing with SpongeBob or customers, but his joy is quashed when Mr. Krabs reassigns him to restroom duties. Unfortunately, Karen is still upset, even snapping at a customer who requests a Krabby Patty. A knocking is heard at the front door: it's Karen 2, who repeatedly slams into the front door. Plankton pops out from inside her, asking what's wrong, and she tells him he didn't program her with arms. Plankton sees Karen at work, and becomes uneasy, then a wave of customers pushes Karen 2 and Plankton into the Krusty Krab. Karen and Karen 2 argue, reaching the point that Karen jumps out of her post, ready to fight Karen 2. Mr. Krabs uses the opportunity to make money from people betting on the fight.
Karen and Karen 2 fight, striking each other. When Plankton falls out of Karen 2, she accidentally runs him over, and Karen is horrified. Karen 2 is unconcerned, which infuriates Karen, who finally destroys her replacement. She talks to a wounded Plankton, who sees the error of his ways in replacing her. Karen's power runs out, and Plankton takes the battery from the destroyed body of Karen 2 and puts it into her. Karen revives, thinking it was all a dream. She and Plankton return to the Chum Bucket, and Karen 2's screen explodes. Mr. Krabs is upset over the loss of Karen, but when SpongeBob suggests that he rebuild Karen 2, he has Squidward wear Karen 2's screen like a mask and take orders.
Plankton was controlling Karen 2, as shown in one scene.
This is one of the few episodes to have Plankton for a large amount of the episode, but isn't the main antagonist.
This is the second time Plankton replaces Karen with another love. The first time was in "Enemy In-Law," in which, he fell for Mr. Krabs' mother, Betsy Krabs.
This is the third time Karen has zapped Plankton. In "Enemy In-Law," after he's dumped by Betsy Krabs and told her she "crawled back" to him, and once more in "Frozen Face-Off," she zapped him for leaving her for dead in the tundra.
This episode marks the third appearance of a face on Karen. In "Single Cell Anniversary," she had a happy face as Plankton serenaded her. In "Walking the Plankton," she was giddy upon learning she's going on a cruise.
Usually people push the Krusty Krab door open, but this time it's pulled.
When Karen and Karen 2 argue, they use computer terms against each other. When Karen says she'll "crumble" Karen 2's cookies, it's an actual computer term; cookies are files that contain information about a user that are sent to the central computer with each request. The server uses the information to customize data sent back and to log the requests of the user.
This is the second time Plankton replaces Karen with another machine: in "Komputer Overload," Plankton blames Karen for his repeated failures to obtain the secret recipe and builds three machines to help him with that task.
In Comic Crazy: Take 2 there is a comic story that shares a very similar plot where Karen leaves the Chum Bucket and works for the Krusty Krab.
When Karen 2 says that Plankton didn't design her with hands, she seems to have hands when she disconnects Karen's hardrive. However, this was only one arm.
When Karen was depressed because Plankton was cheating and she started working she did not ask for the Krabby Patty formula because she was mad at Plankton, and didn't want to help him. Also it may be that Mr. Krabs doesn't want Karen to work SpongeBob's job, in case she becomes loyal to Plankton again.
This episode premiered on March 24, 2013 in the UK and Ireland after the local Kids' Choice Awards.
When SpongeBob and Mr. Krabs were booting up Karen in Mr. Krabs' office, the screen said "Karen Classic." This could be a parody of the Macintosh Classic, which is an Apple Macintosh computer from 1990.
Karen 2 tells Plankton that she has no arms, but earlier she turned off Karen Classic with an arm that came out of a panel.