[The episode begins at the Krusty Krab. A mother and a baby passes by and is greeted by a polite gentleman. A raspberry noise is heard. The mother turns and gives the gentleman an angry look, thinking it was him who made the noise. The noise is heard again. They turn and see a long line standing in the Krusty Krab. It turns out to be Mustard Day and SpongeBob is giving away mustard to the customers.]
SpongeBob: Mustard, mustard, step right up for your mustard! [flips the mustard container] Some mustard for you. Eh, eh, eh. [sprays mustard on a little boy's Krabby Patty]
[The mustard forms into a t-rex and it roars mustard in the boy's face.]
Boy:[his face is covered in mustard] Cool!
SpongeBob:[flips the mustard container] A bit of the yellow for you. Doy. [sprays mustard on Frankie Billy's Krabby Patty]
[The mustard forms into a sailboat. It whistles and rings its foghorn before it melts onto the patty. Frankie Billy laughs and skips away. Nancy Suzy Fish comes up and whispers something in SpongeBob's ear.]
SpongeBob: Oh, okay. [winks at Nancy Suzy Fish] Eh. [hops and spins the mustard container before spraying the mustard into a handsome man] And a Mr. Mustard for you.
Nancy Suzy Fish:[purrs as walks with her Mr. Mustard while licking him] Mmm, yummy.
SpongeBob: Hyah! [attempts to give mustard to Frank, but the mustard container is all out and it cough out a small drop of mustard]
SpongeBob: Hang on, folks, I'll be right back with more mustard. [hops on the mustard container and drives on it like a car] Whoo! [drives to the kitchen and goes to the condiment cabinet] Let's see. Ketchup. [slides ketchup door to mayonnaise door] Mayonnaise. [rolls up mayonnaise door to mustard door] Oh, mustard. [opens doors mustard door to find Mr. Krabs in it]
Mr. Krabs: Did you use up all me mustard?
SpongeBob:[stammering nervously] What?
Squidward:[filing his tentacle] Oh, who gives a flying fish about mustard?
SpongeBob:[gasps] But Squidward, without mustard I wouldn't be able to make a—
Mr. Krabs: Krabby Patty! That's right, you're both hereby ordered to go down into the mustard mines! And bring me back more mustard!
Squidward: Mustard mines?
Patrick:[comes out of the condiment cabinet and is covered with mustard] Mmm, mustard. [takes a container off his head and grabs a packet of mustard] Uh... Ah. [squirts mustard in his mouth, eats it and burps]
Mr. Krabs:[wipes mustard off his face] And you are going down to the mustard mines too.
Walter Haddock:[offscreen] I wouldn't do that if I was you. [creepily comes in and spits on the grill]
[SpongeBob wipes the grill clean.]
Walter Haddock: That old mustard mine is cursed.
SpongeBob:[hugs Mr. Krabs in fear] Cursed?
Mr. Krabs:[pushes SpongeBob away] What kind of curse?
Walter Haddock: It's, uh, er, one of those—The Mummy's Curse.
Mr. Krabs:[snickers] There's no such thing as mummies.
Walter Haddock:[holds up a creepy picture of his mother] We've all got mummies. Eh? [giggles] Mm-hmm. I've been in that mine. No one that enters gets out alive. [makes a creepy smile as a shrieking noise is heard; a spider crawls into his mouth and thunder claps]
SpongeBob: You got out and you're alive.
Walter Haddock: Ah, but am I?
Patrick: Yeah, you're standing right there.
Walter Haddock: But am I? [walks away in a creepy fashion]
Mr. Krabs: Yeah, you're right—[notices that he's gone, but he sees his foot] Hmm.
Squidward: I see your foot.
Walter Haddock:[slides his foot back] No, you don't.
SpongeBob: Ah, his foot's gone!
[The scene changes to SpongeBob, Patrick, and Squidward at the entrance to the mustard mines.]
Squidward:[looks at the map] This map doesn't show us where the mustard vein is located. Well, let's just start picking.
Patrick:[picking his nose] Way ahead of you, pal.
Squidward: Ugh. [turns and looks at the map again]
[Patrick reaches into his nostril and picks out his brain.]
Patrick: Ooh. [smears his brain on Squidward's shirt]
[Squidward turns and grunts in disgust. Patrick gets scared and runs over to SpongeBob. Squidward picks up his pickaxe and heads into the mustard mines.]
SpongeBob and Patrick:[gasps and skips into the mines] ♪Oh, a-mining we will go! The mustard, it will flow! [bounce up and down really hard] With pick and axe without the facts! There's nothing that we know! Ta-da!♪
[SpongeBob and Patrick's violent bouncing causes a landslide and falling rocks seals off the entrance, much to their horror.]
Squidward: Huh? You nitwits! How will we get out now?
Patrick: Ah, we're trapped in a mine! We'll never get out!
[Patrick goes into frantic panic and runs up and down the mine walls. He curls in a fetal position and acts crazy. He punches his chest and passes out.]
Squidward:[sighs and goes to check on Patrick] Krabby Patty, stat.
[SpongeBob takes out the ingredients and makes a perfect Krabby Patty. He gives it to Squidward and he feeds Patrick the patty. Patrick swallows the patty and slowly wakes up.]
Squidward: He's coming 'round.
Patrick:[weakly] Squidward. I—I need—
Squidward: What can I get for you?
Patrick:[pulls out the Krabby Patty from his mouth] I need a little mustard for the Krabby Patty.
Squidward:[drops Patrick down in disgust] Why do I even bother? Maybe there's a back door.
SpongeBob and Patrick: Hey, wait for us!
[SpongeBob and Patrick run over to Squidward.]
[They stop at a long, deep shaft.]
Squidward: I wonder how deep it is.
SpongeBob: I'll check. [picks up a pebble, goes over the edge and falls into the shaft] Wahhh! [appears next to Squidward and Patrick] Don't bother jumping. That shaft has no bottom. Let's take the escalator.
Squidward:[pushes SpongeBob and Patrick aside] All right, spread out! [goes on the escalator]
[SpongeBob and Patrick follow and go on the escalator with Squidward. They see coal miners go up the escalator.]
SpongeBob: Coal miners.
[They see sulfur miners go up the escalator. The awful smell from the sulfur makes SpongeBob, Patrick, and Squidward cover their noses.]
Patrick: Sulfur miners.
[They see a group of kids go up the escalator.]
SpongeBob: Unaccompanied minors. [drum sting]
[SpongeBob, Patrick, and Squidward walk off the escalator.]
Squidward: All right, let's get to work, chowderheads.
[They go in separate directions while bumping into each other for a little bit. SpongeBob digs up a yellow rock with his pickaxe.]
SpongeBob: Hey, I found something yellow. [pulls the yellow rock out of the wall; he was happy at first, but turned sad] Never mind, it's just gold. [throws it away]
Patrick: All I'm getting is dumb old diamonds. [throws and kicks several diamonds]
SpongeBob:[carrying a handful of gold nuggets] This must be the Mummy's Curse that old guy was talking about. [throws the gold nuggets in the stalagmite]
Squidward: Gold and diamonds? [digs up sand from the wall] Gold dust! No, no, it's just sand.
[Up above the surface, Ryan is minding his own business playing in the sandbox. Suddenly, the sand begins to form a whirlpool and sucks Ryan down underneath.]
Ryan: Whoa! [screaming]
[Ryan comes out from the hole Squidward dug up and he runs around in panic.]
Squidward:[upon seeing Ryan] Ah.
[Ryan continues to run and scream in panic until he calms down when he goes up the escalator.]
Squidward: Uh, what was that?
SpongeBob:[sighs] The greatest treasure of all, a child.
[SpongeBob, Patrick, and Squidward resume their task. All of a sudden, SpongeBob begins to sniff out something. He sniffs the wall and punctures a hole on it with the pickaxe. It turns out that he dug up a payphone underneath the wall. The phone rings and SpongeBob answers it.]
Mr. Krabs:[with angry customers yelling in the background] SpongeBob, where's me mustard?
Jennifer Millie: I want some mus—[Mr. Krabs pushes her away with his foot]
SpongeBob: On the way, sir, as soon was we find it. [hangs up but answers again] Love you. [hangs up again]
Squidward: Oh, we'll never find that mustard vein. [pokes the wall with the pickaxe and the wall crumbles into a hole, leading him to the subway] Oh, what is this? [wonders around the subway]
Subway PA: Local train approaching station.
[Deep in the tunnel, a train emerges and stops in front of Squidward. The train opens its doors, revealing SpongeBob and Patrick already on board. Squidward stares at them in shock, wondering how they managed to afford a train ride.]
SpongeBob: Hurry up, Squidward, before the doors close!
Patrick: It's the last train of the night!
SpongeBob: Do you have a metro card?
[Squidward frantically searches for a metro card until he finds one under his shirt.]
Squidward: Ah! I got it! [tries to scan his card, but the tumblers keep beeping red]
SpongeBob: Come on, Squidward!
[Squidward tries all his might to scan his card as he watches the train doors close in horror.]
Subway PA: Watch the closing doors.
[Squidward buffs up his arm and the tumbler finally turns green, approving access to it. Squidward runs through the tumblers and frantically heads to the train.]
SpongeBob: Faster, Squidward, faster!
[Squidward makes it, but the doors close on his neck, leaving his body being dragged outside of the moving train.]
Patrick: Hey, Squidward, you really should watch the closing doors.
[Squidward growls and hisses at Patrick in complete anger and frustration.]
Subway PA: This is a local mining train making all stops between Coal and Limestone. Next stop, Condiments.
SpongeBob: Oh, that's our stop.
[The train stops at the condiments vein. The doors open. SpongeBob steps over a battened Squidward and heads to the condiments vein. Patrick runs out and steps on Squidward, but grabs him by the feet.]
Patrick: Come on, Squidward!
[SpongeBob and Patrick scurry into the condiments vein while Squidward, being carried by Patrick, hits his head on the sign. Patrick sets Squidward down. Squidward walks around in a dizzy fashion, but pulls himself together. Squidward knocks on the wall and punctures a hole with his pickaxe. Mayonnaise comes out of the wall and sprays into Squidward's face.]
Squidward: Hmm. [sticks out his tongue] Ah, la, hmm. [licks the mayo] Ah! I've struck mayo!
[SpongeBob punctures a hole on a different wall and a drop of hot sauce flies onto his tongue. He tastes the dropping and his body flares up, burning himself to a crisp.]
SpongeBob: Hot sauce. [his body crumbles into ashes]
[Patrick goes to puncture a wall with his pickaxe, but flips over and falls to the ground; his pickaxe punctures a hole on the wall and ketchup spews out.]
Patrick: I struck blood! [grabs some of the ketchup and tastes it] Oh, no, it's ketchup! [slurps some more]
SpongeBob: We're getting close. [punctures a hole on the ground and mustard comes out; he takes a sample of mustard] Oh. [licks the mustard] Mustard. Ahhh! I struck mustard!
SpongeBob, Patrick, Squidward:[dancing around in circles while twisting SpongeBob's body] ♪Look at all the mustard flow! Look at all the mustard flow! That golden yellow fatty acid treat!♪
[SpongeBob unravels himself, sending Squidward and Patrick flying to another wall. SpongeBob warms himself up and goes to crack open the ground again. But the ground was so thick that is disintegrates his pickaxe.]
SpongeBob: Oh, no, what are we gonna do now?
Squidward: I think we better use our heads.
Patrick: Let's use my head. [pulls his tongue and his pointy head revs up like a power drill]
[SpongeBob and Squidward go to use Patrick's drilling head to drill a hole in the ground. When all of a sudden, they hear a moaning sound. Smoke fumes around the tunnels and a shadowy creature appears.]
SpongeBob, Patrick, Squidward: The mummy!
[The smoke clears and the shadowy figure reveals himself to be none other than the crazy old prospector, Walter Haddock.]
Walter Haddock: Stop!
[Walter Haddock leaps in front of SpongeBob, Patrick, and Squidward, pulls a cork out from his mouth and plugs up the hole in the ground.]
SpongeBob:[gasps] It's the Mummy's Curse guy!
Walter Haddock: There ain't no curse! I just tried to discourage you chuckleheads from mining this mustard!
SpongeBob: Oh, I get it, 'cause the mummy wants the mustard. Mystery solved.
SpongeBob, Patrick, Squidward: Hurrah!
Walter Haddock:[twitches his eye] 'Tain't no mummy! This mustard is sitting on top of 20 million pounds of pressure! If you open her up, she's gonna blow sky high!
SpongeBob: Oh, no curse. No mummy. And no mustard. [sniffs] And I'll have to find another job! [cries and blows his nose on Squidward's nose]
Squidward:[pulls his nose back] Stop. Don't you see? This old coot wants all the mustard for himself! Now uncork that mustard!
Walter Haddock: Hmm? [growls]
Squidward: Oh, put your fists down, old man. I'm not gonna hurt you.
Walter Haddock: Hyah! [punches Squidward in the face]
[Squidward falls over.]
SpongeBob: You were right, Squidward, you're not gonna hurt him.
Squidward:[gets up and is really angry] Why you— [gets punched in the face again] Ow! [gets punched again] I'm gonna— [gets punched and his head spins; then he gets punched again]
SpongeBob: Go, Squidward, you're winning! You're not hurting him at all!
Patrick:[buffs up] Let me try not hurting him. [grabs Squidward and throws him aside] Come on, old-timer! You know you want a piece of me! [Walter Haddock punches Patrick on the head and sends him flying and crashing onto the hole in the ground] Oh.
Walter Haddock: Ow, that hurt!
Patrick: I hurt him! That means I lose.
[Suddenly, the ground underneath begins the shake due to the force of Patrick's fall. Cracks begins to form and Walter Haddock dodges the incoming stalagmites from the ground. The mustard from underground begins to build up pressure and is about to erupt.]
SpongeBob: No, no, no, no, no, no, no! [tries to hold down the pressure, but the mustard begins to fill up inside his body] Whoa....!
Walter Haddock: Adiós, muchachos!
[Walter Haddock laughs manically and bounces around until he calms down when he goes up the elevator. Cracks form underneath Squidward and the crack uncovers a payphone next to him.]
Squidward: Hmm. [phone rings and he answers it] I'll get it. Hello.
Mr. Krabs:[on a mast above the angry customers] Where's me mustard?!
[Pressure builds up as SpongeBob's body grows bigger and bigger from the upcoming mustard. Patrick tries his best by corking up the holes. At the Krusty Krab, the customers continue to riot against Mr. Krabs. One customer is chopping the mast down with his axe. The screen zooms out to reveal volcanic pocket of mustard underneath the Krusty Krab.]
Squidward: Your mustard is coming right up.
Mr. Krabs:[as the mast falls] When?!
[SpongeBob can't hold the pressure much longer as his eyes fill up with mustard. The ground under the Krusty Krab rumbles and erupts a geyser of mustard through the roof. SpongeBob, Patrick, and Squidward bounce up and down on top of the geyser.]
SpongeBob: Wow! Yee-ha! Yeah!
[The mustard fills up the Krusty Krab inside. The customers are now satisfied and go to swim around in the mustard as well as eat their patties with mustard. Among them stands a mummy, who is unimpressed.]