When he leaves for the recording studio, Dennis informs Dee that her boyfriend—real name Kevin Gallagher—is retarded. He remembers Kevin attended special needs classes in elementary school. His sister refuses to believe him. Now, with Dee on a mission to prove her brother wrong, Mac has a pitch for the gang. They need to start their own band, because if a retard can do it and get laid, they certainly should be able to!
Dennis mentions he's always had affection for the idea of becoming a rock god, but Mac immediately disses any skills Dennis might have because his music taste is different from the band's musical direction.
Dennis protests and reminds all of them that there isn't a single person in the pub with any musical ability whatsoever. Frank , however, is quick to point out that nobody needs musical ability to make it as rock stars in the current world.
Mac immediately recruits Frank into the band and Dennis leaves the Gang completely appalled. Mac then invites Frank to take he and Charlie out to buy instruments. After choosing a guitar based entirely on how he looks when he holds it, Mac is shocked to discover that Charlie can actually play keyboards. Charlie admits its a skill he's had forever and he's always wanted to be onstage. Of course, Charlie would prefer to be behind a curtain on stage, but Mac is already more inspired because someone in the band can actually play an instrument.
Frank is about to be arrested for pounding the drums too loudly. Everything is settled when Frank announces he's found the perfect set to buy.
Meanwhile, Dennis shows Dee his elementary school year book where "Special K" appears to be drooling all over himself in his picture. Dee dismisses the evidence because Kevin is only seven years-old in the picture. Dennis antagonizes Dee further when he says she can date whomever she pleases, but she should ask herself if she really likes Kevin or if she's only gold digging a retard. Dee lets it slip that she's picking Kevin up in an hour.
This starts a sinister game in which Dennis keeps score in regards to Kevin's normalcy versus Kevin's mental retardation. Retarded - one, Normal - zero. When she discovers that Kevin still lives with his mother, it doesn't help his case for "normal. As the two of them argue over which category has more points, Kevin comes out of his room. Dee and Dennis clam up, uncertain if Kevin overheard the two of them constantly repeating the words "retard", "normal" and numbers associated with each.
To break the silence, Dee introduces Dennis as their ride to the studio. Kevin immediately hugs Dennis with what Dennis terms "retard strength. At Frank and Charlie's place, the band is hard at work sounding terrible. A spontaneous band meeting irrupts where Frank and Mac determine that practice is for pansies as real rock stars destroy property. Following the logic, if they all deface property the music will come to them. Charlie doesn't want his place busted up, so the decide to take the destruction elsewhere.
After demolishing a hotel room, Frank is angry to discover that his credit card was used to secure the room. Dee watches a cartoon with her boyfriend Lil' Kevin. She stares at him while he laughs loudly and disjointedly at the ensuing childish action on screen.
She informs him that his shirt is on backward, but the man dismisses it out of hand. He continues to throw popcorn into his mouth while he laughs. He doesn't bother to swallow before he drinks from his juice box. Dee, horrified, realizes that Lil' Kevin holds the popcorn bowl in a way that would certainly score in Dennis' game. She says to Kevin, "We need to break up. Frank prefers an early sixties Beatles approach that will instill trust in young women's mothers.
Mac prefers a Sid Vicious punk approach. Both men wear their preferred costumes while they argue over the name of the band. Frank wants to call the band The Pecan Sandies and claims that the title is a double entendre. Mac dismisses the idea in favor of Chemical Toilet because he thinks it will get them all laid faster.
Charlie rushes out of the office to present their first song dressed as Bob Dylan. The lyrics have the appearance of a page from a coloring book.
The song is called " The Nightman ". As they perform the song, Frank and Mac are appalled by Charlie's lyrics and claim that the song is too disturbing for the band's artistic direction. Charlie defends the song and sings more of it to convince them that they're missing the meaning. Mac immediately attempts to recruit Dennis into the band as a new front man.
Dennis insists on wearing spandex, believing it will make him a rock god. Frank can't play drums and Mac can't play guitar so practice isn't going very well when Dennis shows up in his costume. Mac hates Dennis' costume, but gives him Charlie's lyrics anyway.
Before they can practice with their new front man, Sweet Dee comes into the room and announces that she broke up with Kevin. She claims that her inability to tell if Kevin was retarded or not retarded was too much stress for her to handle. Dennis then announces from the practice stage that Lil' Kevin actually is not retarded. He informs Dee that he was just messing with her. Dee berates Dennis and rushes out to salvage her relationship with Kevin. Shocked, Mac prompts Dennis for the truth.
Dennis tells Mac that Kevin is "totally retarded. Both Frank and Mac are put off by Dennis' glam rock swagger so they kick him out of the band. Charlie, meanwhile, is holed up in his apartment as he huffs spray paint from a sock and tries to perfect The Nightman.
Dennis joins him and insists that they join forces. When Dennis drops the shades to Charlie's window, inspiration strikes them both as they realize the titular "Nightman" in the song needs a " Dayman " to battle within the quickly appearing rock opera.
The two of them enthusiastically put together the song for their own band. Local legends of glam rock Paddy's Pub is the site for the concert where both bands appear on stage. Charlie and Dennis call their band Electric Dream Machine. Both men wear foil, science fiction outfits and Dennis announces to the unusually crowded bar that they will experience "sexual magic. Charlie rushes off of the stage with his dreams completely destroyed.
At the concert, Dee flirts with her boyfriend Kevin and confides that she only broke up with him because of what Dennis told her. Kevin giggles at the prospect of being thought of as retarded. Dee tries to laugh it off with him, but then asks him to his face if he's retarded or not. Kevin isn't amused anymore. When Chemical Toilet takes the stage, Lil' Kevin takes their spotlight. He kicks Frank and Mac off-stage and is cheered by the bar crowd that recognizes and supports him.
Lil' Kevin then performs a free-style rap that he dedicates to Dee. The rap is very insulting to Dee and puts to rest the issue of Kevin's mental illness. After Kevin calls Dee a "bitch" to her face, Dennis looks thoughtful.