Hank is outraged when a conservative church member attempts to outlaw Halloween.
Hank and his buddies work on constructing a haunted house for the local school. Meanwhile, Luanne attends a Bible study meeting. The group leader introduces Junie Harper, a new, outspoken member of the church whom Hank considers a busybody. Junie tells the impressionable teenagers that Halloween is a holiday for witches and Satanists. When Luanne returns home, she repeats what Junie said about trick or treating being devil worship--a notion that raises Hank's ire. Later, Junie tells Luanne she is sponsoring a Hallelujah House, a "righteous alternative" to haunted houses. When Junie learns that Bobby's school is sponsoring a haunted house, she threatens the principal, Mr. Moss, with a lawsuit (claiming separation of church and state). Left with little choice, Moss cancels the haunted house.
Peggy suggests that the haunted house be held inside the family garage. Later, Hank initiates Bobby in the fine art of trick or treating by covering Junie's house with toilet paper. As a furious Junie exits the dwelling, Hank and his son run for cover. But Junie gets a good look at Bobby's face and reports him to the police. Hank takes the blame for the incident, but out of Peggy's earshot, he praises the boy as a "regular Halloween hellraiser." Later, Luanne tells Bobby that his father is a Satanist. At first, Bobby dismisses the notion, but after recollecting several of Hank's comments about Halloween, the boy comes to believe Luanne may be right. Meanwhile, Junie convinces the City Council that her house was attacked by Satanists. As a result, the Council passes a curfew that, in effect, cancels Halloween. Despite this, Hank vows to teach his son "the true meaning of Halloween come hell or high water."
Luanne and Bobby attend Hallelujah House, where Junie pushes her own religious agenda. Meanwhile, Hank and Peggy sit by the garbage hoping trick or treaters will stop by the garage to see the haunted house. When Hank learns that his son attended Junie's anti-Halloween church party, he takes action. Despite the threat of arrest, Hank dons his Devil's costume from childhood and walks down the street yelling, "trick or treat." Soon after, other residents muster the courage to join him, and a parade of neighbors gather in front of Junie's home. Hank tells his son he will be given candy if he joins the festivities. Junie, however, warns he will be sent to hell. Bobby decides to go trick or treating--not because of the candy, but because of his wish to be with his father. Later, the boy tells Hank that despite what he said in front of Junie, he does indeed care about the prospect of getting free candy.