The Simpsons win a free spa weekend. At the spa, Homer is nearly killed when a mysterious person locks him into an incredibly hot steam room with a spanner, but he is saved when Krusty the Clown unlocks the door. This prompts Homer and Marge to see Chief Wiggum, who suggests that they seek help from someone who can understand a murderer's twisted mind – Sideshow Bob, who is released from prison, much to Bart's discomfort. To ensure Bart's safety, Wiggum places a shock bracelet on Sideshow Bob's ankle to keep his murderous urges at bay when he comes to live at the Simpson house. Bob asks Homer to list all the people who may want him dead, and follows him around to investigate who the mystery assailant could be. During their day, they end up at a repair shop, where Homer chastises the mechanic, Junior.