Four Years Ago: October 31
Hank and Dean dress up their room like a cemetery and try to scare Dr. Venture. He isn't scared.
Three Years Ago: October 31
Hank and Dean dress up their room like an Egyptian pyramid, complete with mummies. Dr. Venture isn't scared.
Two Years Ago: October 31
Hank and Dean fake a tragic accident in their bedroom. Dr. Venture tells Brock to clean up the room and get the slugs ready. Once the adults go, the brothers wonder what their father was talking about and figure that he's impossible to scare.
When Dr. Venture comes in and asks why Hank hasn't decorated the bedroom, Hank says that he's too old for a haunted room. He tells his father that he got his e-mail by mistake, talking about a malignant melanoma. Dean is in the bathroom, complaining that it hurts to urinate since his last date. Hatred runs in and tells Dr. Venture that the plumbing has broken down and water is spraying out of the electrical sockets. Everyone then announces that they managed to scare Dr. Venture at last.
Later, Orpheus talks to Dr. Venture about how he is hosting a party for the Brimstone Assembly in his rented section that night. Dr. Venture tells him to keep it down and Dermott comes in, dressed for Halloween. Dr. Venture irritably tells him to go back outside and ring the doorbell. As the boy leaves, Orpheus points out that Dr. Venture was hard on the boy but he simply says that he has his reasons.
When Dermott rings the doorbell, Hank and Dean let him in. They realize that he's in costume but he explains that it's a disguise for when they go out pranking later. Hank runs upstairs and gets a garbage bank so that he can go out as either a Bag of Hank or a California Raisin.
Orpheus and his friends the Alchemist and Jefferson prepare for the annual Brimstone Assembly meeting. Jefferson tries to draw a magical circle and the alchemist lies out treat. Red Menace comes early, posing as the Two-Headed Man.
Dermott plans to throw rotten eggs at cars and TPs houses, but Hank has a better idea. He suggests that they spend the night at Old Man Potter's haunted house. Dean doesn't want to go at first but Hank and Dermott call him chicken until he caves.
Dr. Venture and Hatred prepare candy for trick-or-treaters and argue over what candy bars to give them. Hatred points out that they're fifteen miles from the nearest house and have the security system on, and figures that they deserve bigger candy bars.
At the party, Red Mantle argues with himself over drinking too much. Orpheus calls to the meeting to order, activates the magical circle, and welcomes everyone to the gathering.
Two trick-and-treaters finally show up at the Venture compound: Billy and Pete. Dr. Venture reluctantly gives them candy and slams the door, hoping they'll go away. They don't because they've come to hang out.
Orpheus and Jefferson perform a magic illusion for the crowd.
When the trio arrives at the Potter Place, Hank admits that he doesn't know why it has a bad reputation. Dean is pretty sure that it's on the Venture grounds. Dermott and Hank dare Dean to go in first and he finally gives in. As he explores the house, a strange hairless monkey attacks him and someone grabs Dean from behind. He wakes up a few minutes later and finds the monkey, Rico, sniffing his crotch while a man examines him carefully.
The Assembly members continue performing magic for their fellows. Red Mantle prepares to perform his grand illusion by pulling a rabbit out of a hat for real.
Dr. Venture and the others watch on the monitors as a father tries to bring his daughter up for candy and narrowly avoids being killed by the laser sentries. Billy wins the current bet and Rusty serves his "hunchbacks": ketchup and bourbon.
While they talk about Chex Mix, Hank and Dermott wonder where Dean is. Hank wants to go after his brother but Dermott tells him that they should let Dean enjoy the bravest moment of his life.
Dean wakes up on a table with an old man seated nearby. The old man introduces himself as Ben and says that he's been watching Dean ever since he was born. When Dean wonders if he's Old Man Potter, Ben explains that the nearby field is called Potter's Field and it's where all of the people that have died on the Venture grounds are buried. He apologizes for Rico, explaining that he's a recombinant experiment. Dean demands to be released and Ben tells him that he's not a prisoner. He admits that he's surprised at how well that Dean turned out and explains that he brought the boy into the world.
The Outrider and Tatyana perform their "Transfer everyone to Hell" illusion. After facing off against Toaster Face, the Outrider solves the Rubik's Cube and returns the Assembly to Orpheus' quarters. The Alchemist offers to perform his zombie-raising magic, while Orpheus, upset at his ex-wife and her new husband, goes outside for a breath of fresh air.
Hank and Dermott admire the stars and Dermott's flatulence. They're rudely interrupted when the undead dig their way out of the field and the two teenagers run off.
Ben tells Dean that he's a clone, and Dean is understandably upset. The scientist assures him that he worked with Dean's grandfather to create the process. When Dean died for the first time, Dr. Venture loved him so much that he used the cloning equipment and brought him back using Jonas' equipment. As they talk, a bright white light shines outside.
The undead army marches through the forest but Father Christmas emerges from the white light and blasts them to pieces.
At the Venture compound, Dr. Venture is disappointed when three kids manage to work their way through the laser field and get to the front door. Hatred bet that someone would make it, cheerfully collects his money, and hands out candy.
Father Christmas appears at the party and the Assembly realizes that it's the Master in one of his many forms. He chastises them for forgetting the true meaning of Christmas when a baby was born to remind them not to raise armies of the dead.
Orpheus is outside when the three trick-or-treaters come over and ask for candy. He goes in to get them some hors d'oeuvres and realize that his Master is there. The Master complains about the Assembly misusing their magic to summon zombies, and Orpheus is angry that they summoned zombies when there were children around. The Master tells him that everything is cool and Orpheus is his best student, but realizes that there's a lecture coming on. Sur enough, Orpheus tells the Assembly that Halloween is a special night: the night that they put on costumes so that they can become themselves and find out who they really are.
After finding out who he really is, Dean walks home. He goes up on the roof of the main building and Hank joins him, while Dermott goes to watch a Twilight Zone marathon. Hank asks Dean what happened but Dean avoids telling him that they're clones.