Plankton is once again complaining about how he has no customers, with Karen being annoyed by the constant whining. Nat Peterson instantly comes in and asks for a Chum Stick. Plankton at first thinks he is kidding, then Nat says he was serious, then Plankton gives Nat the Chum Stick. After Nat eats the Chum Stick, he says the Chum Stick was so good, he would come back the next day. Plankton is overjoyed at the fact and brags to Karen, who is barely shaken by the fact (A possible clue that Karen is actually paying Nat). Plankton decides to wait with a Chum Stick for Nat. Eight hours later, Plankton wakes up by the clock and realizes it's closing time and concludes that it was not true that Nat was coming back. However, at that moment, Nat appears. Plankton gives him the chum he had been saving, which Nat thinks is perfect after he looks like it was a very appalling meal. Nat says he will come back the next day and the next week, telling Plankton he has a regular customer on his hands.
At the Krusty Krab, Mr. Krabs is bowling, using his money as the bowling balls and pins. Plankton appears, and Mr. Krabs tries to squish him with a spoon. Plankton assures Mr. Krabs that he doesn't need to compete with the Krusty Krab anymore since he now has a regular customer. Mr. Krabs laughs at him and shows off all his customers eating Krabby Patties. Then Nat appears asking Plankton for another Chum Stick in front of Mr. Krabs. Nat carries Plankton back to the Chum Bucket, with Plankton mocking Mr. Krabs and insulting him. Mr. Krabs explains the situation to SpongeBob and orders him to get Nat to eat food from the Krusty Krab and not at the Chum Bucket. Every attempt is unsuccessful, first when SpongeBob simply shows Nat a Krabby Patty, which Nat immediately doesn't like just by smelling it, secondly, SpongeBob fakes a trip off of a rock holding Nat and pretending the Krabby Patty is coming straight for his mouth, thirdly, SpongeBob transforms into Karen and pretends to give Nat a chum stick which is a Krabby Patty, he ties up and gags Karen so they won't notice him, fourthly, Mr. Krabs and SpongeBob trick Nat into going into a shortcut leading to the Chum Bucket which really leads to the Krusty Krab, they make chum Nat doesn't like. Mr. Krabs bursts into tears, saying that he cannot afford Plankton to have even just one customer. SpongeBob says that if he wants Nat to eat at the Krusty Krab, he will have to make chum as good as Plankton. This gives Mr. Krabs the idea to steal the chum recipe.
That night, Mr. Krabs sneaks into the Chum Bucket trying to steal Plankton's recipe but Plankton catches him with the spoon security system. SpongeBob then grabs Plankton and starts talking about the irony of the situation, but Plankton then uses the spoon security system on SpongeBob. After Plankton reveals the name of his system, Karen shows, on screen, that Nat is heading for the Chum Bucket with a fortune. Nat comes back telling Plankton that the Chum made him sick twice since Nat only pretended to like the food so Karen would pay him so that Plankton would stop complaining. Because of this, Plankton feels miserable again and realizes that he never had a regular customer. SpongeBob tells Mr. Krabs to escape, but Mr. Krabs decides to stay and laugh at Plankton's misery.
The first clue that Nat hated Plankton's chum was when the second time Nat came to the Chum Bucket, Nat looked like he hated it, but he lied and said: "It's perfection!"
The second clue is that he said he doesn't like Krabby Patties and that he doesn't have any friends but in one scene, he can be seen sitting at the Krusty Krab eating a Krabby Patty with other people.
The third clue that Nat hated Plankton's Chum was when Mr. Krabs made Nat eat his brand of chum. When Nat ate the new chum, he said that it was the "second foulest thing he had ever tasted," so that might mean that Plankton's chum was the foulest thing he had ever tasted. That also means he hated the Chum Bucket's chum more than the Krusty Krab's chum.
This also proves that Plankton can't even make chum better than Mr. Krabs, which is the only thing he is good at making.
Nat is seen eating chum again in "Chum Bucket Supreme"; however, this time is only because (along with his friend Ivy/Pilar) he enjoyed saying the slogan "Chum is Fum" despite still being disgusted by the food.
Mr. Krabs in this episode shows an extreme level of pettiness as he apparently doesn't want Plankton to have even one customer, despite meaning it would save him the grief of stopping Plankton from stealing the patty formula. Meaning he either thinks that Nat not being his customer would ruin his business, or he's so petty he doesn't want Plankton to succeed in any way. Regardless, this further expands Mr. Krabs' evil and cruel nature.
In numerous times throughout the series, Nat was shown disliking Krabby Patties, this could be because Karen also paid him to lie about disliking Krabby Patties just as much as he lied about liking chum.
In "Missing Identity," when Nat was at work, they said his name was Peterson. It has now been confirmed that that was his last name.
Running Gag: Nat getting chum, and SpongeBob and Mr. Krabs trying to get him to eat Krabby Patties and someone's skin getting peeled off (see below).
This is the second time Mr. Krabs steals other formulas. The first being in "Best Frenemies."
When Nat came to the Chum Bucket the second time, he ate two chum sticks, but he only paid for one.
Plankton started waiting for Nat at 10:00 A.M. and ended at 5:57 P.M. That's 3 minutes before closing time for both the Chum Bucket and the Krusty Krab.
This and The SpongeBob SquarePants Movie contradict one another. In both this episode and the movie, Plankton says he never had a customer, although The SpongeBob SquarePants Movie was made before this and was supposed to be the last episode chronologically.
Part of this episode takes place on Wednesday and Thursday because Nat says that he is coming back the next day and the day after that and the week after that, indicating that the "day after that" part is Saturday.
When Mr. Krabs was showing his customers to Plankton, Nat was seen in the background as a customer. Maybe it's because he was just coming to get Plankton as he knew he was at the Krusty Krab.
The dollar that Nat gave to Plankton disappeared after Nat left.
When Plankton asks Nat that if he had any friends, Nat said no. However, Nat has been seen with other Bikini Bottomites in other episodes. Again, he could have been lying to Plankton.
When Karen is shown taped to the wall, there is tape over her screen, which restricts her speech even though she has no mouth.
When SpongeBob tries feeding Nat the Krabby Patty, the cheese is missing in the next scene.
Nat does not reveal his name to Plankton, but Plankton somehow already knows it.
He might have known it though from his attempts in the Krusty Krab.
At the beginning when Plankton is crying, he is on the floor. In the next scene, he is on Karen. Also, when he is complaining at the beginning, he rips his skin off, but later, when he's on the floor crying, his skin is back.
Mr. Krabs says "I locked all the exits until you give it a try," which doesn't make sense. The correct way to say it is, "I will keep all the exits locked until you give it a try."
It is unknown why Nat didn't just go back out of the Krusty Krab, as soon as he discovered that the shortcut to the Chum Bucket was actually an alternate route to the Krusty Krab.
When Mr. Krabs is crying, he is on the chum that Nat hated, but when his eyes turn into lightbulbs, the chum is gone.
When Plankton looks out the door to see if Nat is coming, the Krusty Krab and its road are missing.
When Nat goes to smell the Krabby Patty, there is no animation that shows him bending over.