It begins with the Mermaid Man and Barnacle Boy theme song.
After the narrator announces the name of the episode ("The Secret Meeting") it shows Mermaid Man and Barnacle Boy spying on the Dirty Bubble. He is taking a bus to Bikini Bottom. The two heroes decide to stop whatever evil he is doing. Then the scene cuts to the Dirty Bubble coming out of the bus, laughing, and Mermaid Man and Barnacle Boy watching. Then, Man Ray, Jumbo Shrimp. Atomic Flounder and Sinister Slug join the Dirty Bubble. Mermaid Man and Barnacle Boy are worried about this team-up. The Dirty Bubble welcomes the villains to the B.G.A.T.F.B.C, which shall be held at the Evil Hotel, April 3, at noon. Mermaid Man and Barnacle Boy discuss what to do. Mermaid Man acknowledges that they are out-manned, but they are one step ahead of the villains. He takes a shell and uses it as a phone. He asks for the "ocean's greatest heroes" and is told to hold.
The narrator then says, "Meanwhile, outside Motel Evil..." and the scene shows the villains gathering around the building. They enter the building to find two men in white coats sitting at a long table reserved for the villains. The Dirty Bubble says the two men have to leave. One man, who is really Mermaid Man, says he thought it was set aside for the I.J.L.S.A. The Dirty Bubble demands to know what that is, and Mermaid Man takes off the white coat, revealing who he is. The villains are surprised. Mermaid Man introduces the villains to the I.J.L.S.A. First the Elastic Waistband is seen, then Professor Magma, followed by Miss Appear, and the Pi-Right Ponderer. They begin to battle. Barnacle Boy is touched by the Atomic Flounder, grows an evil arm, and is knocked out. The Dirty Bubble fires Man Ray out of his mouth towards the Elastic Waistband, who blocks with his stretching belly. Mermaid Man jumps over to the Evil Arm on Barnacle Boy, who taunts him. The Evil Arm forces Barnacle Boy to swing fists at Mermaid Man. The Elastic Waistband asks what they should do, and Mermaid Man jumps and swings on a chandelier and spins several times in mid-air. He jumps on Barnacle Boy's shoulder and starts wrestling with the Arm. It continues to taunt Mermaid Man, and he pulls Barnacle Boy past Professor Magma, using him as a shield, and attacks the Atomic Flounder, who collapses. The Sinister Slug is seen crawling up a wall behind Mermaid Man. The Slug spits at Mermaid Man. He jumps out of the way and the glop lands on the Atomic Flounder. The slime from the Sinister Slug hardens and Mermaid Man makes the Evil Arm touch the Atomic Flounder. It explodes and Barnacle Boy wakes up. Mermaid Man then uses the hairnet on the Pi-Right Ponderer as a net and gathers the villains in the hairnet. Mermaid Man demands to know what the villains' group name is, which turns out to be the Bad Guys All Together for Book Club. The villains sneer, saying they can't arrest them for reading. Mermaid Man confirms this and tells the audience that no one can arrest you for reading. The show ends, and the credits are shown.
Chorus: Faster than light! prepared to stop crime! It's Mermaid Man and Barnacle Boy! If you're in a jam, It's Mermaid Man and Barnacle Boy!
Fish Head: The Adventures of Mermaid Man & Barnacle Boy! Tonight's episode: "The Secret Meeting"! [cut to a shot of the Mermalair] Deep in the Mercave, something strange takes Mermaid Man's attention!
Barnacle Boy: The Dirty Bubble? What's he doing at the bus stop?
Mermaid Man: Looks like he's got a one way ticket to Bikini Bottom! And there's only one thing he could be up to in Bikini Bottom, Barnacle Boy!
Barnacle Boy: That's right, Mermaid Man!
Mermaid Man and Barnacle Boy: EVIL!
[a bus arrives and the Dirty Bubble gets off it]
Dirty Bubble: Haherhaherherherher!
[Mermaid Man and Barnacle Boy look at each other]
Fish Head: The terrible Man Ray!
Dirty Bubble: Huh! So glad you could make it!
Man Ray: I wouldn't miss this for the world, Dirty! HAHAHAHAH.
Fish Head: The most powerful Of All crustaceans, it's Jumbo Shrimp! It's the Atomic Flounder, the abomination of a nuclear experiment gone horribly wrong! And the terror of the sewers, the man-eating Sinister Slug!
Dirty Bubble: We join forces at last.
Mermaid Man: It's worse than I could have imagined! A team-up!
Dirty Bubble: Welcome to the BGATFBC! [the Dirty Bubble gives the villains cards]
Everyone: Muhahahahahahahha! [Mermaid Man puts on some binoculars and looks at Man Ray's card]
Mermaid Man: April 3rd, 12 of noon! That's tomorrow!
Barnacle Boy: Holy...
[at this point the tape breaks and has to be fixed before it can be put back in the VCR]
Barnacle Boy: Gripin' guppies, Mermaid Man! We gotta do something!
Mermaid Man: Not so fast, little flipper! We are far too outmanned! But fear not. We are always one step ahead of EVIL!
Fish Head: Our hero of the bride puts up a call!
Mermaid Man: To the ocean's greatest heroes! [indistinct phone chatter from the person on the other end on the line] Yeah, I can hold.
Fish Head: Meanwhile, a sinister horde congregates outside Hotel Evil!
Dirty Bubble: Right this way, gentlemen! [the crew comes through a door]
Jumbo Shrimp: Hey, what's going on in here?
Dirty Bubble: Huh? Oh, I'm dreadfully sorry gentlemen, you must be in the wrong room! This room is reserved for the BGATFBC.
Mermaid Man:[in a disguise] That's funny. I thought it was aside for the I.J.L.S.A.
Dirty Bubble: I.J.L.S.A? What in coral caverns is that?
[Mermaid Man and Barnacle Boy take off their hats]
All Bad Guys: Mermaid Man and Barnacle Boy!
Mermaid Man: That's right! [they both jump out of their coats] Now, before you have to say goodbye, say hello to some friends! [He throws some wind, and it breaks the door, somebody comes out] The Elastic Waistband!
Barnacle Boy: Greet the hottest crime fighter in the country! [he pours out lava] Professor Magma!
Professor Magma:[Speaks weird language]
Mermaid Man: The illusive Miss Appear! [She appears] And The Pi-Right Ponderer with his hairnet of knowledge!
Pi-Right Ponderer: Do we really exist?
Mermaid Man: Together, we are The International Justice Lodge Of Super Aquantences!
Dirty Bubble: Let's Get em boys! [A shot of the bad guys running is shown, A shot of the good guys running is shown, A shot of the jumbo shrimp running is shown, A shot of mermaid man flying is shown, Mermaid man Punches jumbo shrimp, Jumbo shrimp throws mermaid man to the wall]
Jumbo Shrimp: Do not tussle with the BGATFBC! [mermaid man falls from the wall]
Pi-Right Ponderer: Violence resolves nothing.
Man Ray:[The Elatic Wasteband does a pose] Good night, balloon boy! [Miss Appear appears and takes away man ray's gun]
Miss Appear: Professor Magma! Catch! [Professor Magma melts the gun]
Barnacle Boy: Step aside, you covious cod! My beef is with the bubble!
Atomic Flounder: RAAAA! [He touches Barnacle Boy on his shoulder]
Barnacle Boy: Nuclear Touch![The nuclear touch shows an arm coming out, and it punches Barnacle Boy right in the face]
Mermaid Man: Fracturing furniture! Hang tight buddy! [The arm hits barnacle boy, again and again, Mermaid Man jumps toward Barnacle Boy, The Dirty Bubble eats Man Ray and spits him out at mermaid man, but Elastic Waistband jumps in the air, opened his belt and stopped Man Ray]
Mermaid Man: Hang in there, my daring deputie. [a face grows out of the hand]
FaceHand: Your daring deputy is nothing right now! But I'd be happy to pass along out the message! If he ever wakes up that is!
[FaceHand tries to hit Mermaid Man with Barnacle Boy's body]
Mermaid Man: Swirling Shrimp! That fiend has taken control over Barnacle Boy!
Elastic Wasteband: What do we do, Mermaid Man?
Mermaid Man: I'm glad you asked! [Mermaid Man jumps onto the chandelier and swings off of it and jumps onto Barnacle Boy] I believe that if The Atomic Flounder were to touch that wretched growth, it would cause a chain reaction, reversing the polarity, and the molecular level, restoring Barnacle Boy to his natural state!!
Does that sound about right, Professor Magma? [A cut to Professor Magma]
Handface: You'll never do it! You don't have the moxie!
Mermaid Man: That's what you think, curd! [he picks up HandFace and Barnacle Boy] Shield! [Professor Magma turns in the shape of a shield, and Mermaid Man Picks him up, Atomic Flounder grabs shield, and Mermaid Man throws him down] Ha, Ha, Ha! [The Sinister Slug was on the wall behind him]
[Mermaid Man looks behind himself]
Sinister Slug: GRRRR! [Sinster Slug spits out slime at Mermaid Man, Mermaid Man avoids it, and it hits Atomic Flounder]
[Atomic flounder struggles to move]
Mermaid Man: The Sinister Slug's slime has got you stationary and stiff! Which means, your time is up, Hand!
[He pushes HandFace toward Atomic Flounder fin]
HandFace: Not Nuclear Toooooouuuuuuch! [HandFace disappears]
Barnacle Boy: Great Gravy! What just happened?
Mermaid Man: l'll tell you about it later, now let's take out the trash!
Pi-Right Pottener: Please, you can use my hairnet of knowledge.
Mermaid Man: Thank you, Ponderer.
Dirty Bubble: No! No! You guys don't understand! It's not what you think! [Bad guys are shown running away from Mermaid Man and Barnacle Boy, who swoop them up in the Hairnet of Knowledge]
Mermaid Man: You really thought you were going to get away with it, did you? First up, villains, what is BGATFBC?
Man Ray: It stands for the Bad Guys All Together For Book Club!
Mermaid Man: Book Club? You mean you weren't going to destroy a library or something?
Man Ray: Why would we do that? We're almost to the new chapter!
Atomic Flounder: What are you going to do, lock us up for reading?
Jumbo Shrimp: Yeah! You can't imprison us for reading!
Mermaid Man: That's right. Remember, kids, no one can imprison you for reading!
The team of The International Justice League of Super Acquaintances looks much different. Captain Magma is changed to Professor Magma and is just a pile of lava, Miss Appear looks similar to Wonder Woman, and has color changes, and Elastic Waistband has the power to puff up and a different costume. The Quickster has also been replaced by "the Pirate Ponderer." This may be due to it being a lost episode.
Also, Mermaid Man refers to the IJLSA as the International Justice Lodge of Super Acquaintances.
The end credits of the episode have the same layout as the end credits in the SpongeBob SquarePants series with the name of the creators of SpongeBob SquarePants credited.