Benny wants to impress a girl named Della. When he finds out that her dog Puffles has died, he decides to win her over by bringing Puffles back to life. He steals a potion from his grandmother's cupboard to resurrect Puffles. Shortly after Benny uses the potion, things start to go horribly wrong, as one can expect when meddling with the dead. Not only has the revival of Puffles made him completely evil, but Benny poured too many drops of the potion into the ground, causing it to spread and unleash other animals from the grave. Benny's grandma explains that the animals' souls have moved on; that's why they are demon animals. The animals terrorize Whitechapel, causing chaos. When Ethan's father has a dinner party, demon animals arrive all around the house and Sarah, Benny and Ethan must kill them all before Ethan's parents catch them.