The highly-anticipated eighth book in the #1 New York Times, Wall Street Journal, and USA Today bestselling series, with over 10 million copies in print!

Jack and June, now separated from their friends, have just discovered something beyond frightening: an evil, other-dimensional fortress. Inside, a vile new villain does Thrull's bidding: gathering critical information about the mysterious Tower. Should Thrull's plan succeed, nothing will stop Rezzoch the Ancient, Destructor of Worlds, from coming to this dimension and unleashing ultimate devastation.

Quint and Dirk, fresh off their epic side quest, join jack and June for an impossible mission: infiltrate and destroy the evil stronghold. If they succeed, they can end the end of the world—for good! If they fail, our dimension may be doomed...

But Jack's Cosmic Hand suddenly seems to have a mind of its own. As the horrifying truth of the Cosmic Hand becomes clear, the Last Kids on Earth must decide what part they will play in the battle to come...