Pac-Man Fever is the 20th episode of Season 8. It aired on April 24, 2013.
Concerned about the physical toll the second trial took on Sam, Dean benches his brother from hunting until he heals up. So, when geektastic hacker Charlie stumbles upon a case and finds the boys, Dean decides it's time to teach Charlie how to be a hunter-in-training. While happy to see "her highness," the boys suspect Charlie is hiding something; a secret that could get her killed.
Dean wakes up at a desk in a mysterious retro office, garbed as a military doctor. Roaming the halls, Dean finds a number of bodies and a newspaper whose date reads 1951, and as he waits for an elevator a number of creatures approach from his flank.
Twenty-four hours earlier, Sam wakes as Dean returns to the Men of Letters base, Sam having grown considerably more weary in the time since the last trial. Sam insists on keeping up with the mission to recover Kevin Tran, but when he can scarcely point a gun, Dean orders him to remain behind. At this point, the boys receive an e-mail from Charlie claiming to be in the area, with a case for them to work on.
Directing her to the base, Sam and Dean learn from Charlie that she's taken an interest in hunting, and follows all their exploits in the Carver Edlund books. But now she's stumbled on a case of a man with liquefied internal organs. With Sam in no condition to hunt, Charlie volunteers to accompany Dean on the case, proving her competence on the firing range and dragging Dean through an honest-to-Chuck montage of outfit-shopping for her new FBI role. Charlie and Dean reach the coroner's office to inspect the bodies. Charlie is nervous and fumbling her words. The coroner Jennifer seems oddly insistent that Dean present the proper FBI paperwork before allowing him to inspect the bodies. The pair leave in temporary defeat, resolving to break into the office later. Elsewhere two video game-playing teens stumble upon another putrefied body.
At the newest crime scene, Dean presses Charlie to take the lead again, but the pair soon find that Sam has beaten them to the scene. While Dean berates Sam for pushing himself too hard, Charlie learns from the witnesses that the coroner took the body, while one of the youths noted a blue handprint on his arm. Frustrated, Dean leaves the pair behind to break into the coroner's office, but arrives to find they've beaten him to it.
Before they can investigate, the coroner herself returns to finish up some paperwork, and Charlie volunteers to distract her while Sam and Dean conduct their investigation. As Charlie awkwardly presses the woman for fashion advice, Sam and Dean learn that the bodies have already been burned, Sam noting something familiar about the blue handprint. The coroner finally dismisses Charlie, but the three manage to get away before being caught.
Back at the base, research leads Dean to believe that the killings are the result of a Djinn off-shoot, identified by their blue eyes and handprints. Charlie makes an excuse to leave for snacks, though Sam and Dean note something off in her behavior. Later in her own apartment, Charlie pours over her various fake IDs, and donates money from various accounts on computer, before a noise drives her to the door. As she turns around, she finds the coroner Jennifer standing before her, her eyes glowing blue.
Unable to reach her by phone, Sam and Dean track Charlie's phone to her apartment, finding the cell phone trashed among her stash of IDs and laptop. Finding that all the money on Charlie's computer gets funneled into a coma patient name Gertrude Middleton, Dean visits the brain-dead woman at the Kansas hospital, and recognizes from the nurse's report that the woman must be Charlie's mother. The mother had been in an accident picking up her daughter from a sleepover years earlier, while the daughter apparently disappeared.
Charlie wakes in abandoned warehouse, as the Djinn coroner explains that her kind feeds off of fear, and begins the consumption process through Charlie's arm. Meanwhile, Dean catches Sam up on his findings, as the research leads to the coroner's false identity and a nearby abandoned shipping warehouse.
Sam and Dean enter the warehouse, finding an unconscious Charlie, while Jennifer attacks a weakened Sam. Dean manages to kill Jennifer before she can inflict any real harm, though the brothers soon find the typical Djinn antidote fails to rouse Charlie. Sam reasons that he'll have to wake Charlie of the Djinn dream state from within, and Dean quickly concocts a potion to knock himself out and enter the dream.
Dean awakens in the scene from earlier, but finds himself saved from the approaching Soviet vampire monsters by a Sarah Connor-looking Charlie in an eyepatch! As Dean explains the Djinn's dreamscape feeding process, Charlie reveals that the scenario is that of a video game she'd reprogrammed and illegally released years earlier, appearing more in nightmares than in dreams. Dean explains that they killed the Djinn, to which Charlie asks if they killed the second, as in the real world we see Sam confronted with the monster's partner: her son.
Back in the video game, Charlie explains that she has repeatedly beaten the level, only for the settings to become harder as she tries to defend patients in a hospital. Dean soon sees that the patients are none other than Charlie's mother and Sam, before the vampires corner them in the patients' room. Outside, Sam manages to defeat the younger Djinn, but barely.
Dean realizes that since these particular Djinn feed off of fear, it isn't the monsters keeping them stuck in the dream, but rather Charlie's fear of accepting her mother's death. Charlie breaks down, revealing that she was the one to call her parents to pick her up from the sleepover, leading to their fatal accident, and that she keeps her mother alive hoping to one day finally apologize. Dean urges her to let it go, and as she drops her gun the monsters suddenly disappear. Dean and Charlie finally awaken from the dream, shortly after which Charlie again prepares to say goodbye to the boys. Charlie assures Sam that he'll survive his ordeal with the trials much as his book counterpart would, before telling Dean her next destination is her mother's hospital. Charlie tells Dean she loves him, to which Dean says "I know," and the two part ways once more. Inside the base, Dean interrupts Sam's apology with a hug, and resolves to track down Kevin Tran.
Over at the hospital, the nurse assures Charlie she can take all the time she needs, before Charlie settles in to read 'The Hobbit' to her mother one last time, as her mother had done for her as a girl.
Charlie: Holy Awesome! Too bad they got wiped out. Though that is what they get for the sexist name.