Mystify the Magician — 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.

Christopher, Jalil, April, David, and Senna thought they'd seen it all. Especially after "visiting" Neptune's watery world and then ultimately finding themselves in Atlantis. Once again, they've managed to find a way to the next land -- hoping it will be the passage back to the earth they know. Back to the real world.

But when they wash up on a beautiful beach, they quickly realize that they've still not quite made it back home. That they've arrived in Eire. And it's not the modern-day Ireland they've read about in class. This is a land of giants, leprechauns, and yes, more gods. But Christopher and the others have experience with these beings. The real problem is that Merlin is closing in, and this time he will not be outsmarted. And he will not leave without Senna. . . .