"Gustav and Fernie's adventures in the Dark Country continue as they search for their families. But as they get closer to discovering their loved ones' fates, their mission is once again threatened by old foes--as well as some new, even more treacherous ones. Will Gustav and Fernie be able to battle their way through and rescue their families? Or is it too late?"--Back cover.
When Gustav convinces Fernie's safety-conscious father to enter the Gloom Mansion with Fernie and Perlie to help rescue Gustav's father from the Dark Country, there is a prison break from the Hall of Shadow Criminals, endangering them all.
Fernie and Gustav continue their search for their missing families and discover the magical Cryptic Carousel created by Gustav's grandfather which takes them on a fantastical journey through unbelievable places.
Fernie What, an adventurous young horror fan, moves into the house across the street from the dark mansion of a mysterious boy whose residence is haunted by evil shadows.
As Fernie and Gustav battle the Shadow Eater, who seeks The Nightmare Vault for his master, the evil Lord Obsidian, Fernie learns about Gustav's mysterious past and just what happened to his missing parents.
Spider-Man learns that he has a sister he has never known about, but his family loyalties are tested when he discovers his long-lost sibling in an evil villainess known as Pity.
