Becoming lost in the Gloom mansion while trying to capture a spooked cat, Fernie What and Gustav Gloom discover a library filled with astonishing books, a gallery of awkward statues and the evil deeds of the People Taker who wants to steal Fernie's family.

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?" --