(+ character appears outside of the story).
- Patchy the Pirate+ (original airing only)
- Potty the Parrot+ (original airing only)
- SpongeBob SquarePants+
- Incidental 107
- Squidward Tentacles
- Incidental 41 (2 cameos)
- Patrick Star
- Eugene H. Krabs
- King Neptune (mentioned)
- Green kid (debut)
- Orange kid (debut)
- Sheldon J. Plankton
- Old Man Jenkins
- Scallops and clams
- Incidental 23
- Incidental 14
- Incidental 45
- Incidental 151
- Incidental 49
- Incidental 106
- Incidental 67
- Incidental 63
- Incidental 118
- Incidental 42
- Incidental 2
- Incidental 60
- Incidental 30
- Incidental 73
- Incidental 27
- Incidental 68
- Incidental 47
- Incidental 22
- Incidental 65
- Fred (blue)
- Incidental 37A
- Incidental 36
- Incidental 64
- Incidental 8
- Incidental 93
- Incidental 48
- Incidental 92
The episode begins on one day in Bikini Bottom, SpongeBob wipes the grill with a sponge (made from part of his own tongue) at the Krusty Krab. He proclaims that it is freshly clean and tries to convince a customer to eat a Krabby Patty that was on the grill. When SpongeBob goes back inside to cook the patty, the customer asks Squidward why he does not want a Krabby Patty, and he replies that he has seen what SpongeBob cleans the grill with. It goes back to SpongeBob, who is on his way to the freezer for a patty when he slips on a puddle of water. Upon closer inspection, SpongeBob observes that the puddle is coming from the sink, which is clogged with water. As he is trying to figure out how to unclog the drain, Patrick comes in and slips as well. He helps SpongeBob try to pull the drain plug.
Eventually, Mr. Krabs overhears them trying to pull the drain plug and stops them before they have a chance. He tells them the story of the Main Drain. He tells them that there was a plug that two kids apparently pulled long ago that ended the world of Bikini Bottom. When they ask him where it is, he becomes nervous and tells them to go away. The two go outside and SpongeBob accidentally steps on Plankton. He peels him off his shoe and then they ask him about it. He becomes nervous as well and tells them to go away. SpongeBob says that he heard it from Mr. Krabs, and Plankton claims Mr. Krabs was lying. They ask him where it is they once again do not get the answer. They turn to Old Man Jenkins, but he yields no results.
They then go on an adventure to find the plug by dragging Patrick's house around. Just before they pull the plug, Mr. Krabs and Plankton stop them and tell the story of how they were the ones that pulled the plug when they were younger. They explain that they lied because they did not want SpongeBob and Patrick to look for it. Unfortunately, Patrick had already pulled the plug when they were telling the story and everything (including themselves and the Bikini Bottomites) is sucked into the drain.
Patrick then sits up in his bed, telling SpongeBob that everything was "the most realistic story he has ever heard," indicating everything that happened was only part of the story that SpongeBob was reading. However, the pulling sound is played, meaning the drain is going to suck the ocean for real, as the episode ends.
- Patrick turning on music on his radio whenever Mr. Krabs is about to tell the story of the Main Drain.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
• A Pineapple Luau - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Title card]
• Salty Krab Jig - Michael Bolger, Nicolas Carr [SpongeBob exits the freezer]
• Jolly Little Roger - Michael Bolger, Nicolas Carr [SpongeBob cleaning the grill]
‣ Dramatic Bridge 4 - Phil Green [SpongeBob slipping]
• Vibe Q Sting - Nicolas Carr ["Hey, where'd all this water come from?"]
‣ Clumsy C - Bernd Gesell [sink clogged]
‣ Killer Birds [#36] - Gregor F. Narholz ["Pull the drain plug."]
• Steel Licks 6 - Jeremy Wakefield ["What in Neptune's bathtub do you think you're doing, lad?"]
• Unknown Vibe Sting 5 - Nicolas Carr ["Hmm... One sec."]
‣ Agitation Bridge 3 - Phil Green ["...of the Main Drain."/"It happened a long time ago..."]
• In the Cooler Tension Build Up - Nicolas Carr, Dick De Benedictis ["...putting them under its spell."]
‣ Domestic Fun (a) - Ernest Tomlinson [kids wandering through the ocean]
‣ Domestic Fun (b) - Ernest Tomlinson [they pull the drain plug]
‣ Epic Adventure - Dick Stephen Walter [kids sucked down the drain]
‣ Dramatic Encounter - Gregor F. Narholz ["And nobody was ever heard from again."]
• Steel Licks 7 - Jeremy Wakefield ["I don't know where it is!"]
• Goofy Conversation 2 - Nicolas Carr, Barry Anthony ["Mr. Krabs sure has a lot of baggage about drain dealies."]
‣ Drama Link (G) - Hubert Clifford ["The main drain?"]
• Comedic Conversation - Nicolas Carr, Steve Marston [Plankton says there is no main drain]
• Down in Davey Jones Locker - Nicolas Carr ["Why on earth would Krabs tell those two blunderers about the main drain?"]
‣ Befuddled Gent - Phil Green ["Old Man Jenkins!"]
• Steel Sting - Jeremy Wakefield ["I have no idea."]
‣ Bucaneers [#91] - Harry Bluestone, Emil Cadkin ["Patrick, we need to find that drain!"]
‣ Shock - Cornelus Joh Bolten [Patrick thinking]
• Steel Licks 21 - Jeremy Wakefield [Patrick babbling]
• Seaweed 2 - Steve Belfer [SpongeBob blowing bubbles]
‣ Variety Link (d) - Dick Stephen Walter [bus-shaped bubble]
‣ Editor's Falling Over (B) - Dick Stephen Walter [bubble pops]
• Great Idea Patrick - Nicolas Carr ["I know!"]
• Steel Licks 8 - Jeremy Wakefield [SpongeBob blows a bubble]
• Skipping to School - Sage Guyton, Jeremy Wakefield [Patrick's house floating up]
‣ Drama Link (D) - Hubert Clifford [SpongeBob and Patrick scream]
• Steel Licks 15 - Jeremy Wakefield ["Another miserable day..."]
• Steel Licks 33 - Jeremy Wakefield ["Oh, how are we gonna find the center of the ocean now?"]
• Steel Licks 32 - Jeremy Wakefield [SpongeBob and Patrick thinking]
• Great Idea Patrick - Nicolas Carr [Patrick gets an idea]
‣ The Jovial Buccaneers [#32] - John Fox [Patrick pulling his house]
‣ Hide and Seek [#17] - Harry Bluestone, Emil Cadkin [they find the drain]
‣ Finger of Fear - Fredric Bayco ["Why would we do that?"]
‣ Dramatic Impact (3) - Ivor Slaney ["No!"]
‣ Dramatic Impact (2) - Ivor Slaney [SpongeBob and Patrick gasp]
‣ Domestic Fun (a) - Ernest Tomlinson [flashback to Krabs and Plankton as kids]
‣ Epic Adventure - Dick Stephen Walter [everything sucked down the drain]
• Steel Licks 1 - Jeremy Wakefield ["We had to lie to keep you from looking for it."]
‣ Dramatic Impact (6) - Ivor Slaney [Patrick pulls the drain plug]
‣ Epic Adventure - Dick Stephen Walter [everything sucked down the drain]
• Steel Licks 6 - Jeremy Wakefield [ending]
- This episode is available on the Legends of Bikini Bottom, Triple Pack 3, Big Hits: Volume 2, The Best 200 Episodes Ever, Sunđer Bob Kockalone DVD 6, The SpongeBob SquarePants Collection, Season 7 Volume 2, The Best of Bikini Bottom, SpongeBob SquarePants Vol. 12, The SpongeBob SquarePants 8 Season DVD Collection, Kids Double Pack, Kids Double Pack: Volume 3, Complete Seventh Season, and Next 100 Episodes DVDs.
- This is the only episode in the "Legends of Bikini Bottom" miniseries that does not have a strange character.
- This episode, as well as the other episodes in the miniseries, was available on the Legends of Bikini Bottom DVD, released on November 16, 2010, two months before it aired on American television.
- Though it was revealed that this episode was only a story being read to Patrick by SpongeBob, the entire population of Bikini Bottom was sucked away before: in the episode "A Flea in Her Dome," everyone was sucked into Sandy's treedome.
- The Main Drain, which sucks in all of Bikini Bottom, obviously refers to the end-of-the-world scenario "killer strangelet."
- Like his arms and legs, SpongeBob's tongue can also be detached and reattached. This was previously proven in "Fools in April."
- This is the second time Mr. Krabs and Plankton are shown as friends and kids. The first was "Friend or Foe."
- On the Legends of Bikini Bottom DVD cover, some of the stories are being sucked down into the main drain, such as "The Monster Who Came to Bikini Bottom," "Welcome to the Bikini Bottom Triangle," "The Curse of the Hex," and "Trenchbillies."
- This episode reveals that SpongeBob is aware that Squidward thinks his life sucks, as he added a scene where Squidward says, "Another miserable day..." in his story.
- A storyboard image appears on the special, Behind the Scenes: Legends of Bikini Bottom.
- When SpongeBob said, "Patrick, we need to find that drain," the road suddenly disappears.
- When SpongeBob puts the danger sign on the floor, the lever beside the freezer disappears.
- When Mr. Krabs turned off the lights, it is the left side, but when he finished the story, the switch suddenly changed positions. The next scene shows that the switch is above SpongeBob, hanging on the ceiling.