Lost in the mysterious woods of the Unknown, two brothers named Wirt and Gregory run into a jaded old woodsman who warns them to beware the terrifying Beast that roams the dark forest.

Is millionaire Quincy Endicott's sprawling mansion haunted by a beautiful ghost, or is the tea baron going mad? Greg and Fred the Horse are on the case! Meanwhile, Wirt and Beatrice get trapped in an armoire while searching for loose change.

The origin of Wirt and Greg’s descent into the Unknown reveals itself.