As Billy is tired of all the rules in his house, he can't resist the urge to try his father's new motorcycle. As expected, the motorcycle breaks down and Billy asks Grim to repair it. However, Grim's scythe turns the motorcycle it into a wild, supernatural vehicle, which in turn transforms Billy's parents and everyone else around it into undead creatures and motorized monsters. In the end, Mandy makes Billy tell the truth about breaking the motorcycle in the first place, at which point his parents and everyone else return to normal.