 Someone breaks into Grim's trunk and releases his Mojo Balls, causing everyone in Endsville to be infected by supernatural rage and senselessly fight each other.Following a suspicious trail of chicken feathers, Billy, Mandy, Grim, and Irwin travel to various locations from the series such as the Underworld, Jack's pumpkin patch, and even Billy's backyard to simultaneously recover the Mojo Balls and find out who released them.After defeating the brain-eating meteor from "Little Rock of Horrors", which crashed in Billy's backyard, Billy reveals he was the one who opened Grim's trunk hoping to free "Moe and Joe".