Entertain the End — K.A. Applegate

There is a place that shouldn't exist -- but does. There are creatures that shouldn't exist -- but do. Welcome to a land where all of your dreams and nightmares are very real -- and often deadly. Welcome to Everworld.

April, David, Christopher, and Jalil have come to the end of the line. Senna, their only passage back to the real world, is gone. And she's definitely not coming back. But that doesn't change any of the harm Senna managed to cause in Everworld. And April and the others know it's up to them to help Merlin make things right.

But making things right involves another meeting with Hel. Hel, who before meeting April and the others, had never been outsmarted. Hel, who would be more than happy to see them dead -- or even better, suffering for eternity. And eternity's a mighty long time.