When the spirit of an evil Viking warrior returns to life in the body of Harold's squeaky dog toy, it wants revenge against the rabbit that trapped it in the first place.

A disfigured guinea pig visits Bunnicula and has plans to banish Chester to the Hole of the Unworthy.

Mina leaves the pets out overnight in the spooky old dog house, not realizing that the doghouse is haunted by the ghost of a playful puppy from the 1930s, who won't rest until someone plays with him.