SpongeBob is out jellyfishing. He catches a jellyfish, gets some of its special jelly, and lets it go. He names it "Twelvy", due to it being his twelfth catch of the day.
He then sees a very rare blue jellyfish which he calls "No Name", who is apparently the only jellyfish in the fields who was never caught, and compulsively tries to get him but to no avail.
Later, SpongeBob goes on his lunch break at the Krusty Krab, and puts the jelly on a Krabby Patty. After Fred asks about the patty and tries it, he sings a song proclaiming its greatness and puts jelly on the patties of all the other customers, who enjoy it as well. Mr. Krabs sees the profitability, and puts the new patty on the menu.
SpongeBob, to his great delight, is tasked to go out and gather as many jellyfish as he can, though he asks Krabs to keep the jellyfish comfortable. He continues to catch jellyfish, and Krabs continues to demand more, until Jellyfish Fields is completely deserted.
SpongeBob concludes that there are "no more" jellyfish to catch, and begins to walk home.
After several close encounters and strange events, No Name captures him in a jar much in the way that SpongeBob catches jellyfish. No Name then takes SpongeBob to a secret factory, where he discovers that Krabs is cruelly treating and killing the jellyfish to extract their jelly for more profit.
Realizing that Mr. Krabs tricked him into catching all the jellyfish and broke his word to keep them comfortable, SpongeBob then understands why No Name brought him here in the first place. He angrily confronts Mr. Krabs for his actions and decides to free the jellyfish to no avail.
Eventually, Mr. Krabs accidentally opens the voice activated door by saying the codeword: "open", freeing all the jellyfish, who then all sting Krabs at once, giving him pain as consequence for his actions against them, and No Name is finally named by SpongeBob: Friend. Having felt so much pain from the jellyfish stings, Mr. Krabs finally decided to take the jelly off the menu for good.
In the UK, the scene where No Name cuts the power to SpongeBob's house is replaced with a shot on the door outside of SpongeBob's house.
The scenes when SpongeBob says goodbye to Twelvey and when No Name makes the power in SpongeBob's house go out were cut in the Fisher Price Interact TV version of this episode.
When Mr. Krabs says "The door will only open if I say open". It only opens the second time he says the word, even though he says "The door will only open if I say open." Although, it is possible that it took a few seconds to activate the door from when he first says "open".
This episode was featured in the SpongeBob Earth Day Marathon that leads up to "SpongeBob's Last Stand" and the story is similar.
The scene where Mr. Krabs said "More!" and looked very morbid has become an internet meme. This meme is known as "Moar Krabs".
This is the first episode to show Mr. Krabs as the main antagonist of an episode.
When Mr. Krabs is riding the bicycle, he wears his headphones on the sides of his eyes which may hint that his eyes and ears may be connected.
SpongeBob picking up the phone and hearing heavy breathing is a reference to the 1979 movie When a Stranger Calls.
When No Name/Friend sneaks into Spongebob's house, he looks like a blob crawling around the floor. When he does this, he resembles ChuChu, a character from the video game Kirby's Dream Land 3.
SpongeBob takes out the wrench and loosens a bolt on the door, but after Mr. Krabs sighs in relief, the bolt is gone.
During the part where Mr. Krabs says "You'll never catch me!", his walkman can be seen in his pocket, then after the scene zoomed out, his Walkman in his pocket is gone.
After Fred finishes his song, you can hear the crowd cheer for him, however, none of the fish are moving at all and only the cheering sound is heard.
When SpongeBob is being followed by the blue jellyfish, he says, "It feels like somebody... wants to sell me something!" However, the captions read "tell" instead of "sell."
Mr. Krabs says, "It will never open unless I say 'open,'" it only opens the second time he says open.
The captions commonly misspell "Krabby Patty" as "crabby patty".
When SpongeBob is only wearing underwear in Jellyfish Fields, his sleeves are still shown.
It's no wonder why SpongeBob didn't get the door open; he didn't even grab the door in the first place!