At the Chum Bucket, Plankton is introducing a new chum sauce, which melts through the pan and later through the floor. Just then, the alarm sounds, informing Plankton about a customer. Plankton goes to receive the order, only to find that he wanted a Krusty Krab product, so Plankton tells him to get those foods and beverages at the Krusty Krab. As he complains over how the people will not buy his food, he feels that Karen wasn't a good employee to him. Then, he threatens to replace his wife with much cooler machines, all three which fail to operate steadily. One of those machines is a toaster with arms and legs, which explodes, but survives. Another which is made of mostly liquid, but popped open and lost its liquid and also survived. The last being a windmill with a hairdryer on its back. Soon, the new inventions were acting aggressively toward each other. Plankton stated that he has had enough of Karen saying it was all her fault for all of his failures. Karen left a note saying that she's tired of being blamed for his failures and has decided to move on. Later, Plankton sics his machines on the Krusty Krab, which startles Mr. Krabs, causing him to send SpongeBob out there and talk to Plankton.
After Plankton had enough of SpongeBob's foolishness for not understanding what he had uttered, Plankton rushes towards the Krusty Krab to demolish Mr. Krabs, but the extension for the machines is not long enough to reach the Krusty Krab, causing it to unplug and turn off the machines. Plankton then sees Karen, who has come back to get her things. He apologizes to her for his blaming and behavior and she accepts his apology. They go back to the Chum Bucket together and the episode ends.
Plankton once again tries to replace Karen in the season 8 episode "Karen 2.0."
These episodes both have similar scenes also.
Knowing that Plankton was born in 1942, it is almost impossible that Karen and Plankton's wedding photo was in color.
The only way this is possible is if they color enhanced it or they got a color photographer (which would have been really expensive because it wasn't a common thing at the time of their wedding, which would have been at least 20 or 30 years from when this episode aired).
It is revealed that Plankton once had hair, as seen in a photo.
The letter from Karen says microorganism, but Plankton reads it as "single-cell organism."
In Indonesia, after Plankton says "I've got a customer to attend to!," the Krabby things is skipped to "Honestly, I don't think anyone in Bikini Bottom would know a decent meal if it looked them right in the eye and said, "Hello! I'm a decent meal, wonderful to meet you! Please pay money for me and then put me in your mouth so your old pal Plankton doesn't lose everything he's spent his entire life working for!!!"
The Bikini Bottom News said that Plankton's invention was attacking the city, yet he only walked across the street to the Krusty Krab and didn't go into the city at all.
It is unknown how the liquid-cooled robot rebuilds itself.
It might have been another unit built just in case one of them broken for any reason.
When Plankton's giant robot rampages through Bikini Bottom, there is no power cord attaching it to the Chum Bucket. However, as the robot advances towards the Krusty Krab, the cord appears.