At SpongeBob's house, he and Patrick are dancing. The music is shaking Squidward's house, so Squidward tells them to lower the volume. When they don't listen, Squidward plays a squeaky tune which sends SpongeBob and Patrick flying into Squidward's house and causes SpongeBob to hit Squidward, lodging his clarinet in his throat which makes Squidward make squeaky notes. When SpongeBob gets the clarinet out of Squidward's throat the reed is still stuck in him. They then go to Sandy who has a plan. She decides to go in a submarine, shrink herself (and the submarine), go into Squidward's body and retrieve the reed. When Sandy goes to get some acorns and nuts from the Treedome she tells SpongeBob to guard the submarine. Patrick walks by and encourages SpongeBob to guard the submarine from the inside. They go in there and guard it when Patrick presses the shrink button, shrinking the submarine. Sandy comes back and notices them. She then has to guide them to Squidward's brain. There, SpongeBob and Patrick start to hit parts of the brain, causing Squidward to lose self-control.
For a moment, SpongeBob and Patrick actually fight each other for control of the vehicle and land in Squidward's stomach, where the gastric acid starts to eat the submarine away. Patrick thinks of an idea: If Squidward can drink soda, then bubbles (gas) would surround them and it would refuel the submarine. Squidward drinks soda and the plan suddenly starts to work. They travel through the throat where SpongeBob removes the clarinet reed by doing what he was "born to do", dance. The reed is removed and the gang celebrates, but is cut short by the sound of the now angered Squidward. He demands them to leave his body and yells at them to "GO!". However, Patrick mistakes it for "grow" and hits the grow button while still being in Squidward's body. Squidward is next seen at the Krusty Krab looking bloated and his stomach in the shape of a submarine. A flush sound is then heard, followed by Patrick, still stuck in the submarine in Squidward's body, claiming the toilet is clogged (again, apparently) Squidward groans.
( ‣ ) Associated production music
( • ) Original music
( ◦ ) SpongeBob music
‣Maui Girl - Harry Bluestone [title card] ‣ ? [dance music] • ? - Nicolas Carr, Barry Anthony [Squidward playing clarinet] • ? - Nicolas Carr ["Oh."] • ? - Sage Guyton, Jeremy Wakefield [SpongeBob trying to get the clarinet out of Squidward's throat] ‣The March of the Ants - Sidney Crooke [x-ray of Squidward's throat] ‣ ? [Sandy's submarine] • ? - Jeremy Wakefield ["Always wanting to do it the hard way."] ‣Tympup A - Sammy Burdson, John Charles Fiddy [Sandy knocks Squidward out] • ? - Nicolas Carr [Sandy knocks Squidward out] •Vibe Sting - Nicolas Carr ["Oops!"] ‣ ? ["Can do, Sandy!"] ‣ ? [SpongeBob guarding the submarine] • ? - Sage Guyton, Jeremy Wakefield [SpongeBob, Patrick enter the submarine] ‣Project X - King Palmer [submarine shrinking] ‣Secret Shadow - John Scott [submarine put into Squidward's nose] ‣Lovely Scenery C - Mladen Franko [Squidward screams] ‣Cosmic Cloud - Trevor Duncan ["SpongeBob and Patrick are piloting a miniature submarine inside my head?!"] ‣Project X - King Palmer [Squidward panicking] ‣Weird Bridge - Roger Roger ["Where are we, Patrick?"] ‣Drama Link (f) - Hubert Clifford ["I'll save you, Sandy!"] ‣Moon Walk - John Fox [submarine breaks down] ‣Dramatic Cue (c) - Ronald Hanmer [SpongeBob floors it] ‣Missile Disaster - John Fox [submarine stuck in Squidward's brain] •Steel Licks - Jeremy Wakefield ["Oh, just your autograph."] ‣On Fire - Gregor F. Narholz [Squidward hitting himself] ‣Danger Force - Norman Dane [submarine lands in Squidward's stomach] ‣Exciting Action B - Mladen Franko [Squidward burps] ‣Missile Disaster - John Fox ["Whee!"] • ? - Nicolas Carr [Sandy smells Squidward's breath] ‣Danger Force - Norman Dane [Squidward's esophagus] ‣ ? [two hours later] ‣Danger Force - Norman Dane ["This stupid hammer won't break anything."] ‣Wild Panic - Gregor F. Narholz ["Whirlpool spin!"] •Steel Sting - Jeremy Wakefield [Squidward coughs up the reed] •Vibe Sting - Nicolas Carr ["Grow?"] ‣Drama Link (b) - Hubert Clifford [everyone screams] ‣The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [The Krusty Krab] ‣Drama Link (f) - Hubert Clifford ["Neptune's trousers!"] ‣Drama Link (d) - Hubert Clifford ["Neptune's trousers!"] ‣The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band ["What's gotten into you?"] ‣Captain Lenoe's - Michael Arthur, Colin Cater, Mick Graves, The Folk Players, Sarah Graves, Simon Ritchie [ending]
Two hours later
This is the first time Squidward goes into Sandy's Treedome. He will go inside there again in the episode “Squid Defense.”
The beginning of the episode is similar to the main plot of “Jellyfish Jam,” in that SpongeBob's loud music makes Squidward angry,
SpongeBob using the Whirlpool Spin to slice apart the reed is similar to the climatic battle in the 1986 anime show Ginga Nagareboshi Gin, where the titular dog decapitates the demon bear Akakabuto with the Zetsu Tenrou Battouga.
When SpongeBob says "Whirlpool spin!" his mouth doesn't move.
When SpongeBob cuts the reed in half, red electricity is seen for less than a second.
When Squidward burps, Sandy smells it even though she is wearing a helmet. However, in “Karate Island,” She could not smell Filthy Phil's body odor.