Scooby-Doo and the gang travel to Chambersburg, a battlefield near Gettysburg, to investigate the mysterious appearance of ghost zombie Civil War soldiers and come face to face with a rival mystery solving gang, the Funky Phantom crew.

Driving through the Rocky Mountains, the Mystery Inc. gang discovers a sleep-away accordion camp run by none other than Weird Al Yankovic! But there is no accordion joy when a horrible dinosaur (a dreaded allosaurus) attacks the camp.