When Lewis and Rose Rita explore an abandoned theatre, they discover an unpublished opera score entitled "The Day of Doom." Ignoring a strange omen, they show it to their music teacher, who heralds "The Day of Doom" a masterpiece. Little do they know that the eerie Henry Vanderhelm, the composer's grandson, arrives with a plan to awaken the dead and enslave the world! Soon, all the adults are enamored—and enspelled—by Henry Vanderhelm. A mysterious fog descends upon New Zebedee and everyone is trapped inside it. It is up to Lewis and Rose Rita to stop the dead coming back to life.