This episode is the third and final part of the three-part story arc that started with "Coon 2: Hindsight" and continued with "Mysterion Rises". Coon and Friends find themselves at the mercy of Cartman who now has the dark lord Cthulhu doing his bidding. Kenny wrestles with the curse of his super power through his alter ego, Mysterion.
The episode begins with Bradley as Mint-Berry Crunch introducing the episode in the same comic book style as Mysterion had done at the beginning of "Mysterion Rises". Toolshed soon asks Mysterion what his superpower really is, like The Coon did in "Coon 2: Hindsight", which leads to everyone discussing their powers. Toolshed has mental power over any tool; The Human Kite can fly and shoot lasers out of his eyes; Mosquito says he got his powers like from a radioactive mosquito; Tupperware mentioned that he was in a car accident until he was put back together with tupperware products; Iron Maiden wears an indestructible suit of armor. Mysterion then mentions that he can't die and brings up events from "Mysterion Rises" in which he was killed after being stabbed but nobody believes him. This leads him to commit suicide by shooting himself in the head. Everyone is distraught over this, but nobody remembers the next day after Kenny comes back to life. When Cartman returns home from New Orleans, he is lectured by his mother because he was supposed to be grounded. Trying to get past her, he attempts the "Lebron James technique" which works and he's allowed to visit Coon and Friends and convince them to come outside to witness the rare "double rainbow". When there is no double rainbow to be seen, Cartman brings out Cthulhu, which scares off Mint-Berry Crunch. Cthulhu then sends the other Coon and Friends to oblivion, where Mysterion decides to impale himself in order to awaken as Kenny in reality.
Mysterion goes to Henrietta, the female goth's house, where the goths are complaining about Cthulhu's actions. Mysterion learns from them that an immortal can only be killed by another immortal when the Goths show him the texts in the Necromonicon. Henrietta's mother comes in and tells her that her brother wants to play with them, who turns out to be Bradley. Once he sees Mysterion, he turns into Mint-Berry Crunch and follows him to The Coon and Cthulhu, who had just killed Justin Bieber and hundreds of his fans at a concert.
Mysterion tells Cthulhu to kill him when a bright light with a man inside appears who is Limahl the Neverending Story singer and former lead singer of 80s new wave band KajaGooGoo. The man first appears to be telling Mysterion that he is his father from a far away planet, and that he was supposed to stop Cthulhu because he was the chosen one. However, it then turns out that he was actually talking to Mint-Berry Crunch, and that Bradley is the chosen one. Mint-Berry Crunch then flies up to Cthulhu and attacks him with berries and the flavor of cool mint. He drags him back to whence he came, saves the other heroes and shuts the hole DP oil had created on the surface of the moon.
The Coon then gets put in the cell with Professor Chaos and Mint-Berry Crunch flies away. All the other boys, except for a distraught Mysterion, are surprised and excited that Bradley has 'real' superpowers and still nobody remembers Mysterion getting impaled in the oblivion. Mysterion announces that he is tired and wants to go to bed. He proceeds to shoot himself in the head leaving the boys shocked by witnessing this. The shot cuts to Kenny's mother suddenly jolting up from and crying in pain as she screams, "It's happening again!" The next scene shows her placing baby Kenny in his bed in his orange parka. She then says with regret to her husband, "We never should have gone to that stupid cult meeting.", implying the Necronomicon is responsible for Kenny's many rebirths and resurrections, along with everyone's amnesia and rewritten memories of his deaths.