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.

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.

"Gustav and Fernie's adventures in the Dark Country continue as they search for their families. But as they get closer to discovering their families' 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 before it's too late?" --