SpongeBob visits Patrick's house and tells him he got in the mail a video of the lost episode of Mermaid Man and Barnacle Boy. They begin watching this video. It begins with the Mermaid Man 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 at 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.
Patrick's television becomes filled with static. Patrick yells angrily and SpongeBob quickly repairs the tape. They start watching again.
Mermaid Man and Barnacle Boy discuss what to do. Mermaid 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 it is, and Mermaid 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, and grows an evil arm, and is knocked out. The Dirty Bubble shoots Man Ray out of his mouth and fires at the Elastic Waistband, who blocks with his stretching belly. Mermaid Man jumps 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 wresting 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 and SpongeBob screams to "Watch out!" The Slug spits at Mermaid Man. He jumps out of the way and the glop lands on the Atomic Flounder. SpongeBob and Patrick are happy. 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 their group villains' 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 end. End credits begin to show.
Patrick asks SpongeBob what is happening. SpongeBob explains end credits, and Patrick and SpongeBob thank Neptune for the rewind button.
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 Pirite 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.
Pi-Right is a spoof on the mineral "pyrite".
The end credits on the video look just like the credits for the show.
In "Mermaid Man and Barnacle Boy V," the team of superheroes were called the International Justice League of Super Acquaintances, but in this episode they are called the International Justice Lodge of Super Acquaintances. They both stand for I.J.L.S.A.
The Mermalair is called the Mermacave.
When Mermaid Man is flipping, planning on how he could get Barnacle Boy back, his mouth never moves.
When SpongeBob is rewinding the tape, you can see that he actually pressed the "Eject" button.
When the Villains are about to enter the building where their headquarters is taking place, the narrator says that "the sinister hoard congregates outside Hotel Evil", but on the sign outside the building it says Motel Evil.
In addition, their cards say Hotel Evil.
While Mermaid Man contacts the other heroes, the narrator says 'Meanwhile' and shows the Book Club beginning. However, the meeting was supposed to take place the next day.