One of the Goth kids has been sent to a camp for troubled children. When she returns, her friends find her changed in a disturbing way. With their very existence threatened, the Goths have to do something drastic. They are forced to ask the Vamp kids for help.
The episode begins with the goth kids sitting in Henrietta's room and reciting poetry written by Edgar Allan Poe. Henrietta's Mom interrupts asking Henrietta to come and speak with herself and her husband. In the living room, Henrietta's father explains that they "know" what she is into and that they will be sending her to a camp for emo kids. Henrietta tries to get out of it, but to no avail.
The next day, behind South Park Elementary, the remaining goth kids, Michael, Pete, and Firkle, discuss what Henrietta had texted Michael before she left. She explained that her parents called her emo and that she was sent to a camp.
This prompts the rest of the goths to go to child protective services to save Henrietta. They explain that her parents abused her by calling her emo. The social worker doesn't understand and Michael and Pete explain that Emos are cynical while Goths are nihilistic AND that Goths believe that the world is "fucked up" but Emos think that THEY are totally "fucked up".
At Troubled Acres, Henrietta is in a white room. After pleading for help, a solitary ficus comes from the floor, confusing Henrietta. The ficus shakes.
Later, at the community bus stop, the goths wait for Henrietta's return. Once Henrietta arrives, the goths realize that camp made her emo.
At school, Henrietta is now with the emo kids.
That night, Michael goes to Henrietta and confronts her about being emo. Henrietta explains that the emos are rising and that Michael can do nothing to stop it. Michael is indeed shocked by this.
Michael after running from Henrietta's house calls Pete and explains the situation before returning home.
As he attempts to go upstairs, his mother and father tell him that he will be going to Troubled Acres. Michael tries to run but his dad grabs him and forces him to the truck and they drive off.
The next day, at Benny's, Pete and Firkle are drinking coffee and discuss how the group is ending. Pete comes up with the idea to get help from the only others who know emos, the South Park Vampire Society.
At the Vamps meeting, Pete and Firkle bust in and apologize for burning down the Hot Topic. They ask for help dealing with the rise in emos, and the Vamps reluctantly agree to help.
The Vamps and Goths spy on Henrietta and the other emos at Henrietta's house. After assessing the situation, the Vampire Leader, Mike Makowski, decides they need to summon Edgar Allan Poe.
At the school library, they summon Edgar and realize that he is more goth than even the goth kids, but agrees to stop the emos.
At Troubled Acres, Michael is tied to a chair. An old, Caucasian man, who's obeying the emos, is told by the emo king, a giant ficus, to make Michael and emo so he puts a ficus next to him and tells him it's easier not to struggle.
Meanwhile, Pete, Firkle, Mike, a black twilight fan, and Edgar make it to Troubled Acres. They almost save Michael, when Firkle reveals to them that he is emo.
After tying the group up, ficus plant are placed in front of them. Pete manages to reach Edgar, who went to Benny's for coffee. He makes Edgar save them by telling him to shoot the emo king. Edgar says the emos are just ficus plants from Lowe's Home and Garden. The rest of the group notices this too. The old man, disagrees saying that they talk to him. Edgar says they are just in vibrating pots. A voice booms in the room, asking the old man if he is scared. When he says yes, Television crews come out and says that he was on Yes, I Was Scared. The host, reveals that really goths, vampire kids, and emos are the same and Firkle is shocked that he betrayed his friends for nothing.
Later at Henrietta's house, Pete and Michael tell her that it was all an elaborate prank. Noticing she is ashamed and upset by this, they lie and tell her that they stopped the emo king. She then "returns" to being goth in time for yet another "confrontation" with her mother.
AV Club gave "Goth Kids 3: Dawn of the Posers" a "C-" rating saying: "Unfortunately, “Goth Kids 3: Dawn Of The Posers” was a fairly limp episode, one that an extra unexpected week of time apparently could not fix. The idea of putting the goth kids front and center is fine: The show hasn’t remotely overused them, and putting them in a new scenario offers up the type of perspective break that South Park does at least once or twice each season. But comparisons to the exponentially better “The Ungroundable” were present throughout the installment, and after watching that episode before tonight’s new one, it’s unclear why Trey Parker and Matt Stone went back to this particular realm if there was nothing new to explore."
IGN gave "Goth Kids 3: Dawn of the Posers" a "7.7" rating saying: "Still, "Goth Kids 3: Dawn of the Posers" had enough good laughs throughout to stand on its own merits. While not the strongest episode of the season, this week's installment did prove that the goth kids still had a bit of juice left in them, albeit probably not a full 22 minutes' worth."